diff --git a/common/listener_common.h b/common/listener_common.h
index 979a34b491..c573388e33 100644
--- a/common/listener_common.h
+++ b/common/listener_common.h
@@ -41,7 +41,9 @@ enum ListenerToTargetMsgKind : u16 {
   LTT_MSG_PRINT = 6,          //! Print an object
   LTT_MSG_PRINT_SYMBOLS = 7,  //! Print all symbols
   LTT_MSG_RESET = 8,          //! Reset the game
-  LTT_MSG_CODE = 9            //! Send code to patch into the game
+  LTT_MSG_CODE = 9,           //! Send code to patch into the game
+  // below here are added
+  LTT_MSG_SHUTDOWN = 10  //! Shut down the runtime.
 };
 
 /*!
diff --git a/game/kernel/Ptr.h b/game/kernel/Ptr.h
index 225a23f579..50d327aa89 100644
--- a/game/kernel/Ptr.h
+++ b/game/kernel/Ptr.h
@@ -8,7 +8,7 @@
 #ifndef JAK_PTR_H
 #define JAK_PTR_H
 
-#include <stdexcept>
+#include <cassert>
 #include "game/runtime.h"
 #include "common/common_types.h"
 
@@ -36,25 +36,19 @@ struct Ptr {
   explicit Ptr(u32 v) { offset = v; }
 
   /*!
-   * Dereference a pointer. Will throw if you do this on a null pointer.
+   * Dereference a pointer. Will error if you do this on a null pointer.
    */
   T* operator->() {
-    if (offset) {
-      return (T*)(g_ee_main_mem + offset);
-    } else {
-      throw std::runtime_error("Ptr null dereference!");
-    }
+    assert(offset);
+    return (T*)(g_ee_main_mem + offset);
   }
 
   /*!
-   * Dereference a pointer. Will throw if you do this on a null pointer.
+   * Dereference a pointer. Will error if you do this on a null pointer.
    */
   T& operator*() {
-    if (offset) {
-      return *(T*)(g_ee_main_mem + offset);
-    } else {
-      throw std::runtime_error("Ptr null dereference!");
-    }
+    assert(offset);
+    return *(T*)(g_ee_main_mem + offset);
   }
 
   // pointer math
diff --git a/game/kernel/kboot.cpp b/game/kernel/kboot.cpp
index 3eb61fa121..59a6a4231c 100644
--- a/game/kernel/kboot.cpp
+++ b/game/kernel/kboot.cpp
@@ -8,7 +8,6 @@
 #include <chrono>
 #include <thread>
 
-#include "common/cross_os_debug/xdbg.h"
 #include "common/common_types.h"
 #include "game/sce/libscf.h"
 #include "kboot.h"
@@ -77,9 +76,6 @@ void kboot_init_globals() {
  * Add call to sceDeci2Reset when GOAL shuts down.
  */
 s32 goal_main(int argc, const char* const* argv) {
-  // Added for OpenGOAL's debugger
-  xdbg::allow_debugging();
-
   // Initialize global variables based on command line parameters
   // This call is not present in the retail version of the game
   // but the function is, and it likely goes here.
diff --git a/game/kernel/kdsnetm.cpp b/game/kernel/kdsnetm.cpp
index a45e965c95..9abcf5c1fe 100644
--- a/game/kernel/kdsnetm.cpp
+++ b/game/kernel/kdsnetm.cpp
@@ -161,7 +161,7 @@ void GoalProtoHandler(int event, int param, void* opt) {
  * DONE, original version used an uncached address and had a FlushCache call, which were both
  * removed
  */
-s32 SendFromBufferD(s32 msg_kind, u64 p2, char* data, s32 size) {
+s32 SendFromBufferD(s32 msg_kind, u64 msg_id, char* data, s32 size) {
   // wait for send to finish or error first...
   while (protoBlock.send_status > 0) {
     // on actual PS2, the kernel will run this in another thread.
@@ -190,7 +190,7 @@ s32 SendFromBufferD(s32 msg_kind, u64 p2, char* data, s32 size) {
     header->msg_kind = (ListenerMessageKind)msg_kind;
     header->u6 = 0;
     header->msg_size = size;
-    header->msg_id = p2;
+    header->msg_id = msg_id;
 
     // start send!
     auto rv = sceDeci2ReqSend(protoBlock.socket, header->deci2_header.dst);
diff --git a/game/kernel/kdsnetm.h b/game/kernel/kdsnetm.h
index 1ebc21d05e..3e4f46bdea 100644
--- a/game/kernel/kdsnetm.h
+++ b/game/kernel/kdsnetm.h
@@ -68,7 +68,7 @@ void GoalProtoHandler(int event, int param, void* data);
  * DONE, original version used an uncached address and had a FlushCache call, which were both
  * removed
  */
-s32 SendFromBufferD(s32 p1, u64 p2, char* data, s32 size);
+s32 SendFromBufferD(s32 p1, u64 msg_id, char* data, s32 size);
 
 /*!
  * Print GOAL Protocol status
diff --git a/game/kernel/klink.cpp b/game/kernel/klink.cpp
index 0682d4d441..b7e0260b48 100644
--- a/game/kernel/klink.cpp
+++ b/game/kernel/klink.cpp
@@ -8,6 +8,7 @@
 
 #include <cstring>
 #include <cassert>
+#include <cstdio>
 #include <common/versions.h>
 #include "klink.h"
 #include "fileio.h"
@@ -81,7 +82,7 @@ void link_control::begin(Ptr<uint8_t> object_file,
           "VERSION ERROR: C Kernel built from GOAL %d.%d, but object file %s is from GOAL %d.%d\n",
           versions::GOAL_VERSION_MAJOR, versions::GOAL_VERSION_MINOR, name, ofh->goal_version_major,
           ofh->goal_version_minor);
-      exit(0);
+      assert(false);
     }
     if (link_debug_printfs) {
       printf("Object file header:\n");
@@ -352,11 +353,20 @@ uint32_t cross_seg_dist_link_v3(Ptr<uint8_t> link,
   // target seg, dist into mine, dist into target, patch loc in mine
   uint8_t target_seg = *link;
   assert(target_seg < ofh->segment_count);
+
   uint32_t* link_data = (link + 1).cast<uint32_t>().c();
   int32_t mine = link_data[0] + ofh->code_infos[current_seg].offset;
   int32_t tgt = link_data[1] + ofh->code_infos[target_seg].offset;
   int32_t diff = tgt - mine;
   uint32_t offset_of_patch = link_data[2] + ofh->code_infos[current_seg].offset;
+
+  if (!ofh->code_infos[target_seg].offset) {
+    // we want to address GOAL 0. In the case where this is a rip-relative load or store, this
+    // will crash, which is what we want. If it's an lea and just getting an address, this will get
+    // us a nullptr. If you do a method-set! with a null pointer it does nothing, so it's safe to
+    // method-set! to things that are in unloaded segments and it'll just keep the old method.
+    diff = -mine;
+  }
   // printf("link object in seg %d diff %d at %d (%d + %d)\n", target_seg, diff, offset_of_patch,
   // link_data[2], ofh->code_infos[current_seg].offset);
 
@@ -367,7 +377,7 @@ uint32_t cross_seg_dist_link_v3(Ptr<uint8_t> link,
   } else if (size == 8) {
     *Ptr<int64_t>(offset_of_patch).c() = diff;
   } else {
-    throw std::runtime_error("unknown size in cross_seg_dist_link_v3");
+    assert(false);
   }
 
   return 1 + 3 * 4;
@@ -463,36 +473,38 @@ uint32_t link_control::work_v3() {
     // state 1: linking. For now all links are done at once. This is probably going to be fine on a
     // modern computer.  But the game broke this into multiple steps.
     if (m_segment_process < ofh->segment_count) {
-      Ptr<u8> lp(ofh->link_infos[m_segment_process].offset);
+      if (ofh->code_infos[m_segment_process].offset) {
+        Ptr<u8> lp(ofh->link_infos[m_segment_process].offset);
 
-      while (*lp) {
-        switch (*lp) {
-          case LINK_TABLE_END:
-            break;
-          case LINK_SYMBOL_OFFSET:
-            lp = lp + 1;
-            lp = lp + symlink_v3(lp, Ptr<u8>(ofh->code_infos[m_segment_process].offset));
-            break;
-          case LINK_TYPE_PTR:
-            lp = lp + 1;  // seek past id
-            lp = lp + typelink_v3(lp, Ptr<u8>(ofh->code_infos[m_segment_process].offset));
-            break;
-          case LINK_DISTANCE_TO_OTHER_SEG_64:
-            lp = lp + 1;
-            lp = lp + cross_seg_dist_link_v3(lp, ofh, m_segment_process, 8);
-            break;
-          case LINK_DISTANCE_TO_OTHER_SEG_32:
-            lp = lp + 1;
-            lp = lp + cross_seg_dist_link_v3(lp, ofh, m_segment_process, 4);
-            break;
-          case LINK_PTR:
-            lp = lp + 1;
-            lp = lp + ptr_link_v3(lp, ofh, m_segment_process);
-            break;
-          default:
-            printf("unknown link table thing %d\n", *lp);
-            exit(0);
-            break;
+        while (*lp) {
+          switch (*lp) {
+            case LINK_TABLE_END:
+              break;
+            case LINK_SYMBOL_OFFSET:
+              lp = lp + 1;
+              lp = lp + symlink_v3(lp, Ptr<u8>(ofh->code_infos[m_segment_process].offset));
+              break;
+            case LINK_TYPE_PTR:
+              lp = lp + 1;  // seek past id
+              lp = lp + typelink_v3(lp, Ptr<u8>(ofh->code_infos[m_segment_process].offset));
+              break;
+            case LINK_DISTANCE_TO_OTHER_SEG_64:
+              lp = lp + 1;
+              lp = lp + cross_seg_dist_link_v3(lp, ofh, m_segment_process, 8);
+              break;
+            case LINK_DISTANCE_TO_OTHER_SEG_32:
+              lp = lp + 1;
+              lp = lp + cross_seg_dist_link_v3(lp, ofh, m_segment_process, 4);
+              break;
+            case LINK_PTR:
+              lp = lp + 1;
+              lp = lp + ptr_link_v3(lp, ofh, m_segment_process);
+              break;
+            default:
+              printf("unknown link table thing %d\n", *lp);
+              assert(false);
+              break;
+          }
         }
       }
 
diff --git a/game/kernel/klisten.cpp b/game/kernel/klisten.cpp
index 9b667c2126..f5825d6e5a 100644
--- a/game/kernel/klisten.cpp
+++ b/game/kernel/klisten.cpp
@@ -5,6 +5,8 @@
  */
 
 #include <cstring>
+#include <cstdio>
+#include <cstdlib>
 #include "klisten.h"
 #include "kboot.h"
 #include "kprint.h"
@@ -133,9 +135,9 @@ void ProcessListenerMessage(Ptr<char> msg) {
       break;
     case LTT_MSG_RESET:
       MasterExit = 1;
-      if (protoBlock.msg_id == UINT64_MAX) {
-        MasterExit = 2;
-      }
+      break;
+    case LTT_MSG_SHUTDOWN:
+      MasterExit = 2;
       break;
     case LTT_MSG_CODE: {
       auto buffer = kmalloc(kdebugheap, MessCount, 0, "listener-link-block");
diff --git a/game/kernel/kmachine.cpp b/game/kernel/kmachine.cpp
index 43b27d187f..c7552cdd35 100644
--- a/game/kernel/kmachine.cpp
+++ b/game/kernel/kmachine.cpp
@@ -366,7 +366,7 @@ int ShutdownMachine() {
   CloseListener();
   ShutdownSound();
   ShutdownGoalProto();
-  Msg(6, "kernel: machine shutdown");
+  Msg(6, "kernel: machine shutdown\n");
   return 0;
 }
 
diff --git a/game/kernel/kmalloc.cpp b/game/kernel/kmalloc.cpp
index 0dc84e9c7b..54375c4e47 100644
--- a/game/kernel/kmalloc.cpp
+++ b/game/kernel/kmalloc.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <cstring>
+#include <cstdio>
 #include "common/goal_constants.h"
 #include "kmalloc.h"
 #include "kprint.h"
diff --git a/game/kernel/kprint.cpp b/game/kernel/kprint.cpp
index 29fbfb56c9..4e228dc9c1 100644
--- a/game/kernel/kprint.cpp
+++ b/game/kernel/kprint.cpp
@@ -7,6 +7,7 @@
 #include <cmath>
 #include <cstdarg>
 #include <cstdio>
+#include <cassert>
 
 #include "common/goal_constants.h"
 #include "common/common_types.h"
@@ -348,10 +349,9 @@ s32 cvt_float(float x, s32 precision, s32* lead_char, char* buff_start, char* bu
       value = (char)rounder;
     } else if (!(ru32 >> 31)) {  // sign bit
       value = 0;
-      throw std::runtime_error("got very large exponent in rounding calculation");
+      assert(false);  // not sure what happens here.
     } else {
       value = -1;  // happens on NaN's
-      //      throw std::runtime_error("got negative sign bit in rounding calculation");
     }
 
     // place number at the end of the buffer and move pointer back
@@ -396,10 +396,9 @@ s32 cvt_float(float x, s32 precision, s32* lead_char, char* buff_start, char* bu
           value = (char)next_int;
         } else if (!(ru32 >> 0x1f)) {
           value = 0;
-          throw std::runtime_error("got very large exponent in rounding calculation");
+          assert(false);  // not sure what happens here.
         } else {
           value = -1;  // happens on NaN's
-          //          throw std::runtime_error("got negative sign bit in rounding calculation");
         }
         *count_chrp = value + '0';
         count_chrp++;
@@ -411,7 +410,7 @@ s32 cvt_float(float x, s32 precision, s32* lead_char, char* buff_start, char* bu
     // however, the rounding flag is always disabled and the rounding code doesn't work.
     if ((fraction_part != 0.f) && ((flags & 1) != 0)) {
       start_ptr = round(fraction_part, nullptr, start_ptr, count_chrp - 1, 0, lead_char);
-      throw std::runtime_error("cvt_float called round!");
+      assert(false);
     }
   }
 
@@ -563,7 +562,7 @@ char* kitoa(char* buffer, s64 value, u64 base, s32 length, char pad, u32 flag) {
  * uses C varags, but 128-bit varags don't work, so "format" always passes 0 for quadword printing.
  */
 void kqtoa() {
-  throw std::runtime_error("kqtoa not implemented");
+  assert(false);
 }
 
 struct format_struct {
@@ -801,7 +800,7 @@ s32 format_impl(uint64_t* args) {
                 }
                 kstrinsert(output_ptr, pad, desired_length - print_len);
               } else {
-                throw std::runtime_error("unsupported justify in format");
+                assert(false);
                 //                output_ptr = strend(output_ptr);
                 //                while(0 < (desired_length - print_len)) {
                 //                  char pad = ' ';
@@ -852,7 +851,7 @@ s32 format_impl(uint64_t* args) {
                 kstrinsert(output_ptr, pad, desired_length - print_len);
 
               } else {
-                throw std::runtime_error("unsupported justify in format");
+                assert(false);
                 //                output_ptr = strend(output_ptr);
                 //                u32 l140 = 0;
                 //                while(l140 < (desired_length - print_len)) {
@@ -893,9 +892,7 @@ s32 format_impl(uint64_t* args) {
                 call_method_of_type(in, type, GOAL_PRINT_METHOD);
               }
             } else {
-              // TODO - if we can't throw exceptions, what is the option?
-              // log, break and continue?
-              throw std::runtime_error("failed to find symbol in format!");
+              assert(false);  // bad type.
             }
           }
           output_ptr = strend(output_ptr);
@@ -916,7 +913,7 @@ s32 format_impl(uint64_t* args) {
                 call_method_of_type(in, type, GOAL_INSPECT_METHOD);
               }
             } else {
-              throw std::runtime_error("failed to find symbol in format!");
+              assert(false);  // bad type
             }
           }
           output_ptr = strend(output_ptr);
@@ -924,7 +921,7 @@ s32 format_impl(uint64_t* args) {
 
         case 'Q':  // not yet implemented.  hopefully andy gavin finishes this one soon.
         case 'q':
-          throw std::runtime_error("nyi q format string");
+          assert(false);
           break;
 
         case 'X':  // hex, 64 bit, pad padchar
@@ -1021,7 +1018,7 @@ s32 format_impl(uint64_t* args) {
             precision = 4;
           float value;
           if (in < 0) {
-            throw std::runtime_error("time seconds format error negative.\n");
+            assert(false);  // i don't get this one
           } else {
             value = in;
           }
@@ -1037,7 +1034,7 @@ s32 format_impl(uint64_t* args) {
 
         default:
           MsgErr("format: unknown code 0x%02x\n", format_ptr[1]);
-          throw std::runtime_error("format error");
+          assert(false);
           break;
       }
       format_ptr++;
@@ -1079,13 +1076,13 @@ s32 format_impl(uint64_t* args) {
         *PrintPendingLocal3 = 0;
         return 0;
       } else if (type == *Ptr<Ptr<Type>>(s7.offset + FIX_SYM_FILE_STREAM_TYPE)) {
-        throw std::runtime_error("FORMAT into a file stream not supported");
+        assert(false);  // file stream nyi
       }
     }
-    throw std::runtime_error("unknown format destination");
+    assert(false);  // unknown destination
     return 0;
   }
 
-  throw std::runtime_error("how did we get here?");
+  assert(false);  // ??????
   return 7;
 }
\ No newline at end of file
diff --git a/game/kernel/kscheme.cpp b/game/kernel/kscheme.cpp
index ebe3164fdc..e85ad1479a 100644
--- a/game/kernel/kscheme.cpp
+++ b/game/kernel/kscheme.cpp
@@ -126,9 +126,7 @@ u64 goal_malloc(u32 heap, u32 size, u32 flags, u32 name) {
  * completely defined.
  */
 u64 alloc_from_heap(u32 heapSymbol, u32 type, s32 size) {
-  if (size <= 0) {
-    throw std::runtime_error("got <= 0 size allocation in alloc_from_heap!");
-  }
+  assert(size > 0);
 
   // align to 16 bytes (part one)
   s32 alignedSize = size + 0xf;
@@ -165,7 +163,7 @@ u64 alloc_from_heap(u32 heapSymbol, u32 type, s32 size) {
 
     return kmalloc(*Ptr<Ptr<kheapinfo>>(heapSymbol), size, KMALLOC_MEMSET, gstr->data()).offset;
   } else if (heapOffset == FIX_SYM_PROCESS_TYPE) {
-    throw std::runtime_error("this type of process allocation is not supported yet!\n");
+    assert(false);  // nyi
     // allocate on current process heap
     //    Ptr start = *ptr<Ptr>(getS6() + 0x4c + 8);
     //    Ptr heapEnd = *ptr<Ptr>(getS6() + 0x4c + 4);
@@ -181,7 +179,7 @@ u64 alloc_from_heap(u32 heapSymbol, u32 type, s32 size) {
     //      alignedSize); return 0;
     //    }
   } else if (heapOffset == FIX_SYM_SCRATCH) {
-    throw std::runtime_error("this type of scratchpad allocation is not used!\n");
+    assert(false);  // nyi, I think unused.
   } else {
     memset(Ptr<u8>(heapSymbol).c(), 0, (size_t)alignedSize);  // treat it as a stack address
     return heapSymbol;
@@ -1122,8 +1120,8 @@ u64 call_method_of_type(u32 arg, Ptr<Type> type, u32 method_id) {
               (*type_tag).offset);
     }
   }
-  // throw std::runtime_error("call_method_of_type failed!\n");
   printf("[ERROR] call_method_of_type failed!\n");
+  assert(false);
   return arg;
 }
 
@@ -1159,7 +1157,8 @@ u64 call_method_of_type_arg2(u32 arg, Ptr<Type> type, u32 method_id, u32 a1, u32
               (*type_tag).offset);
     }
   }
-  throw std::runtime_error("call_method_of_type failed!\n");
+  printf("[ERROR] call_method_of_type_arg2 failed!\n");
+  assert(false);
   return arg;
 }
 
diff --git a/game/main.cpp b/game/main.cpp
index ed189cb233..3687634ebe 100644
--- a/game/main.cpp
+++ b/game/main.cpp
@@ -16,7 +16,6 @@ void setup_logging(bool verbose) {
     auto game_logger = spdlog::stdout_color_mt("GOAL Runtime");
     spdlog::set_default_logger(game_logger);
     spdlog::flush_on(spdlog::level::info);
-    spdlog::set_pattern("%v");
     spdlog::info("Verbose logging enabled");
   } else {
     auto game_logger = spdlog::basic_logger_mt("GOAL Runtime", "logs/runtime.log");
diff --git a/game/overlord/fake_iso.cpp b/game/overlord/fake_iso.cpp
index 6971de0c33..fbf1831f7b 100644
--- a/game/overlord/fake_iso.cpp
+++ b/game/overlord/fake_iso.cpp
@@ -273,6 +273,9 @@ uint32_t FS_BeginRead(LoadStackEntry* fd, void* buffer, int32_t len) {
 
   const char* path = get_file_path(fd->fr);
   FILE* fp = fopen(path, "rb");
+  if (!fp) {
+    spdlog::error("[OVERLORD] fake iso could not open the file \"{}\"", path);
+  }
   assert(fp);
   fseek(fp, 0, SEEK_END);
   uint32_t file_len = ftell(fp);
diff --git a/game/runtime.cpp b/game/runtime.cpp
index 37bfbf2587..002ede5b44 100644
--- a/game/runtime.cpp
+++ b/game/runtime.cpp
@@ -47,6 +47,7 @@
 #include "game/overlord/stream.h"
 
 #include "common/goal_constants.h"
+#include "common/cross_os_debug/xdbg.h"
 
 u8* g_ee_main_mem = nullptr;
 
@@ -75,7 +76,7 @@ void deci2_runner(SystemThreadInterface& iface) {
   server.wait_for_protos_ready();
   // then allow the server to accept connections
   if (!server.init()) {
-    throw std::runtime_error("DECI2 server init failed");
+    assert(false);
   }
 
   spdlog::debug("[DECI2] Waiting for listener...");
@@ -148,6 +149,9 @@ void ee_runner(SystemThreadInterface& iface) {
   kmemcard_init_globals();
   kprint_init_globals();
 
+  // Added for OpenGOAL's debugger
+  xdbg::allow_debugging();
+
   goal_main(g_argc, g_argv);
   spdlog::debug("[EE] Done!");
 
diff --git a/game/sce/iop.cpp b/game/sce/iop.cpp
index dc984c3f00..4546eec398 100644
--- a/game/sce/iop.cpp
+++ b/game/sce/iop.cpp
@@ -203,12 +203,14 @@ s32 CreateSema(SemaParam* param) {
 
 s32 WaitSema(s32 sema) {
   (void)sema;
-  throw std::runtime_error("NYI");
+  assert(false);  // nyi
+  return 0;
 }
 
 s32 SignalSema(s32 sema) {
   (void)sema;
-  throw std::runtime_error("NYI");
+  assert(false);  // nyi
+  return 0;
 }
 
 s32 WakeupThread(s32 thid) {
diff --git a/game/system/Deci2Server.cpp b/game/system/Deci2Server.cpp
index 665beb467f..d9c5d86d96 100644
--- a/game/system/Deci2Server.cpp
+++ b/game/system/Deci2Server.cpp
@@ -217,7 +217,6 @@ void Deci2Server::run() {
     printf("[DECI2] Warning: no handler for this message, ignoring...\n");
     unlock();
     return;
-    //    throw std::runtime_error("no handler!");
   }
 
   auto& driver = d2_drivers[handler];
diff --git a/game/system/IOP_Kernel.cpp b/game/system/IOP_Kernel.cpp
index 21ecdb47fe..65db7d6a10 100644
--- a/game/system/IOP_Kernel.cpp
+++ b/game/system/IOP_Kernel.cpp
@@ -7,17 +7,17 @@
  * Create a new thread.  Will not run the thread.
  */
 s32 IOP_Kernel::CreateThread(std::string name, u32 (*func)()) {
-  if (_currentThread != -1)
-    throw std::runtime_error("tried to create thread from thread");
+  assert(_currentThread == -1);  // can only create thread from kernel thread.
+
   u32 ID = (u32)_nextThID++;
-  if (threads.size() != ID)
-    throw std::runtime_error("thread number error?");
+  assert(ID == threads.size());
+
   // add entry
   threads.emplace_back(name, func, ID, this);
   // setup the thread!
   // printf("[IOP Kernel] SetupThread %s...\n", name.c_str());
 
-  // hack to allow creating a "null thread" which doesn't/can't run but occupies slot 0.
+  // allow creating a "null thread" which doesn't/can't run but occupies slot 0.
   if (func) {
     _currentThread = ID;
     // create OS thread, will run the setupThread function
@@ -47,11 +47,9 @@ void IOP_Kernel::setupThread(s32 id) {
   returnToKernel();
   threads.at(id).waitForDispatch();
   // printf("[IOP Kernel] Thread %s first dispatch!\n", threads.at(id).name.c_str());
-  if (_currentThread != id) {
-    throw std::runtime_error("the wrong thread has run!\n");
-  }
+  assert(_currentThread == id);  // should run in the thread.
   (threads.at(id).function)();
-  printf("Thread %s has returned!\n", threads.at(id).name.c_str());
+  //  printf("Thread %s has returned!\n", threads.at(id).name.c_str());
   threads.at(id).done = true;
   returnToKernel();
 }
@@ -60,8 +58,7 @@ void IOP_Kernel::setupThread(s32 id) {
  * Run a thread (call from kernel)
  */
 void IOP_Kernel::runThread(s32 id) {
-  if (_currentThread != -1)
-    throw std::runtime_error("tried to runThread in a thread");
+  assert(_currentThread == -1);  // should run in the kernel thread
   _currentThread = id;
   threads.at(id).dispatch();
   threads.at(id).waitForReturnToKernel();
@@ -77,9 +74,8 @@ void IOP_Kernel::SuspendThread() {
   s32 oldThread = getCurrentThread();
   threads.at(oldThread).returnToKernel();
   threads.at(oldThread).waitForDispatch();
-  if (_currentThread != oldThread) {
-    throw std::runtime_error("bad resume");
-  }
+  // check kernel resumed us correctly
+  assert(_currentThread == oldThread);
 }
 
 /*!
@@ -130,8 +126,8 @@ void IOP_Kernel::dispatchAll() {
  */
 void IopThreadRecord::returnToKernel() {
   runThreadReady = false;
-  if (kernel->getCurrentThread() != thID)
-    throw std::runtime_error("tried to sleep the wrong thread!");
+  // should be called from the correct thread
+  assert(kernel->getCurrentThread() == thID);
 
   {
     std::lock_guard<std::mutex> lck(*threadToKernelMutex);
@@ -145,8 +141,8 @@ void IopThreadRecord::returnToKernel() {
  */
 void IopThreadRecord::dispatch() {
   syscallReady = false;
-  if (kernel->getCurrentThread() != thID)
-    throw std::runtime_error("tried to dispatch the wrong thread!");
+  assert(kernel->getCurrentThread() == thID);
+
   {
     std::lock_guard<std::mutex> lck(*kernelToThreadMutex);
     runThreadReady = true;
@@ -160,17 +156,14 @@ void IopThreadRecord::dispatch() {
 void IopThreadRecord::waitForReturnToKernel() {
   std::unique_lock<std::mutex> lck(*threadToKernelMutex);
   threadToKernelCV->wait(lck, [this] { return syscallReady; });
-  //  syscallReady = false;
 }
 
 /*!
  * Thread waits for kernel to dispatch it.
  */
 void IopThreadRecord::waitForDispatch() {
-  // if(kernel->getCurrentThread() == -1) throw std::runtime_error("tried to suspend main!\n");
   std::unique_lock<std::mutex> lck(*kernelToThreadMutex);
   kernelToThreadCV->wait(lck, [this] { return runThreadReady; });
-  // runThreadReady = false;
 }
 
 void IOP_Kernel::set_rpc_queue(iop::sceSifQueueData* qd, u32 thread) {
diff --git a/game/system/IOP_Kernel.h b/game/system/IOP_Kernel.h
index c25d312322..ed74e55fb1 100644
--- a/game/system/IOP_Kernel.h
+++ b/game/system/IOP_Kernel.h
@@ -10,6 +10,7 @@
 #include <mutex>
 #include <condition_variable>
 #include <atomic>
+#include <cassert>
 #include "common/common_types.h"
 
 class IOP_Kernel;
@@ -98,8 +99,7 @@ class IOP_Kernel {
    * Resume the kernel.
    */
   void returnToKernel() {
-    if (_currentThread < 0)
-      throw std::runtime_error("tried to return to kernel not in a thread");
+    assert(_currentThread >= 0);  // must be in a thread
     threads[_currentThread].returnToKernel();
   }
 
@@ -126,15 +126,16 @@ class IOP_Kernel {
       // total hack - returning this value causes the ISO thread to error out and quit.
       return -0x1a9;
     }
-    //    printf("poll %d %ld\n", mbx, mbxs.size());
-    if (mbx >= (s32)mbxs.size())
-      throw std::runtime_error("invalid PollMbx");
+
+    assert(mbx < (s32)mbxs.size());
     s32 gotSomething = mbxs[mbx].empty() ? 0 : 1;
     if (gotSomething) {
       void* thing = mbxs[mbx].front();
-      //      printf("pop from msgbox %d %p\n", mbx, thing);
-      if (msg)
+
+      if (msg) {
         *msg = thing;
+      }
+
       mbxs[mbx].pop();
     }
 
@@ -145,11 +146,8 @@ class IOP_Kernel {
    * Push something into a mbx
    */
   s32 SendMbx(s32 mbx, void* value) {
-    if (mbx >= (s32)mbxs.size())
-      throw std::runtime_error("invalid SendMbx");
+    assert(mbx < (s32)mbxs.size());
     mbxs[mbx].push(value);
-    //    printf("push into messagebox %d %p\n", mbx, value);
-    //    printf("mbx size %ld\n", mbxs.size());
     return 0;
   }
 
diff --git a/game/system/SystemThread.cpp b/game/system/SystemThread.cpp
index 790dca6154..f7089f2c19 100644
--- a/game/system/SystemThread.cpp
+++ b/game/system/SystemThread.cpp
@@ -15,7 +15,7 @@
 SystemThread& SystemThreadManager::create_thread(const std::string& name) {
   if (thread_count >= MAX_SYSTEM_THREADS) {
     spdlog::critical("Out of System Threads! MAX_SYSTEM_THREADS is ", MAX_SYSTEM_THREADS);
-    throw std::runtime_error("Out of System Threads! Please increase MAX_SYSTEM_THREADS");
+    assert(false);
   }
   auto& thread = threads[thread_count];
 
diff --git a/goalc/listener/Listener.cpp b/goalc/listener/Listener.cpp
index 50338f6fd6..b724dcdc1c 100644
--- a/goalc/listener/Listener.cpp
+++ b/goalc/listener/Listener.cpp
@@ -182,6 +182,9 @@ bool Listener::connect_to_target(int n_tries, const std::string& ip, int port) {
     listen_socket = -1;
     return false;
   }
+
+  last_recvd_id = 0;
+  last_sent_id = 0;
 }
 
 /*!
@@ -218,7 +221,17 @@ void Listener::receive_func() {
       case ListenerMessageKind::MSG_ACK:
         // an "ack" message, sent by the target to indicate it got something.
         if (!waiting_for_ack) {
-          printf("[Listener] Got an ack message when we weren't expecting one.");
+          if (hdr->msg_id == last_sent_id) {
+            printf("[Listener] Received ACK for most recent message late.\n");
+            if (last_recvd_id != hdr->msg_id - 1) {
+              printf(
+                  "[Listener] WARNING: message ID jumped from %ld to %ld. Some messages may have "
+                  "been lost. You must wait for an ACK before sending the next message.\n",
+                  last_recvd_id, hdr->msg_id);
+            }
+          } else {
+            printf("[Listener] Got an unexpcted ACK message.");
+          }
         }
 
         if (hdr->deci2_header.len < 512) {
@@ -236,6 +249,13 @@ void Listener::receive_func() {
           ack_recv_buff[ack_recv_prog] = '\0';
           assert(ack_recv_prog < 512);
           got_ack = true;
+          last_recvd_id = hdr->msg_id;
+          if (last_recvd_id > last_sent_id) {
+            printf(
+                "[Listener] ERROR: Got an ack message with id of %ld, but the last message sent "
+                "had an ID of %ld.\n",
+                last_recvd_id, last_sent_id);
+          }
         } else {
           printf("[Listener] got invalid ack!\n");
         }
@@ -245,6 +265,7 @@ void Listener::receive_func() {
       case ListenerMessageKind::MSG_PRINT: {
         auto* str_buff = new char[hdr->msg_size + 1];  // plus one for the null terminator
         int msg_prog = 0;
+        assert(hdr->msg_id == 0);
         while (rcvd < hdr->deci2_header.len) {
           if (!m_connected) {
             return;
@@ -338,7 +359,8 @@ void Listener::send_code(std::vector<uint8_t>& code) {
   header->msg_size = code.size();
   header->ltt_msg_kind = LTT_MSG_CODE;
   header->u6 = 0;
-  header->msg_id = 0;
+  last_sent_id++;
+  header->msg_id = last_sent_id;
   memcpy(buffer_data, code.data(), code.size());
   send_buffer(total_size);
 }
@@ -365,9 +387,10 @@ void Listener::send_reset(bool shutdown) {
   header->deci2_header.src = 'H';
   header->deci2_header.dst = 'E';
   header->msg_size = 0;
-  header->ltt_msg_kind = LTT_MSG_RESET;
+  header->ltt_msg_kind = shutdown ? LTT_MSG_SHUTDOWN : LTT_MSG_RESET;
   header->u6 = 0;
-  header->msg_id = shutdown ? UINT64_MAX : 0;
+  last_sent_id++;
+  header->msg_id = last_sent_id;
   send_buffer(sizeof(ListenerMessageHeader));
   disconnect();
   close_socket(listen_socket);
@@ -392,7 +415,8 @@ void Listener::send_poke() {
   header->msg_size = 0;
   header->ltt_msg_kind = LTT_MSG_POKE;
   header->u6 = 0;
-  header->msg_id = 0;
+  last_sent_id++;
+  header->msg_id = last_sent_id;
   send_buffer(sizeof(ListenerMessageHeader));
 }
 
@@ -426,8 +450,7 @@ void Listener::send_buffer(int sz) {
       printf("  OK\n");
     }
   } else {
-    printf(
-        "  Error - target has timed out. If it is stuck in a loop, it must be manually killed.\n");
+    printf("  Timed out waiting for ack.\n");
   }
 }
 
diff --git a/goalc/listener/Listener.h b/goalc/listener/Listener.h
index f8fe829ad9..156df1a36e 100644
--- a/goalc/listener/Listener.h
+++ b/goalc/listener/Listener.h
@@ -65,6 +65,8 @@ class Listener {
   std::vector<std::string> message_record;
   std::unordered_map<std::string, LoadEntry> m_load_entries;
   char ack_recv_buff[512];
+  uint64_t last_sent_id = 0;
+  uint64_t last_recvd_id = 0;
 };
 }  // namespace listener
 
diff --git a/test/goalc/CMakeLists.txt b/test/goalc/CMakeLists.txt
index 01a8d14bde..fdbc5728cc 100644
--- a/test/goalc/CMakeLists.txt
+++ b/test/goalc/CMakeLists.txt
@@ -3,6 +3,7 @@
 set(GOALC_TEST_CASES
 		"goalc/all_goalc_template_tests.cpp"
 		goalc/test_debugger.cpp
+		goalc/test_game_no_debug.cpp
 )
 
 set(GOALC_TEST_FRAMEWORK_SOURCES
diff --git a/test/goalc/framework/test_runner.cpp b/test/goalc/framework/test_runner.cpp
index 41447e323d..63de48aad1 100644
--- a/test/goalc/framework/test_runner.cpp
+++ b/test/goalc/framework/test_runner.cpp
@@ -102,6 +102,12 @@ void runtime_with_kernel() {
   exec_runtime(argc, const_cast<char**>(argv));
 }
 
+void runtime_with_kernel_no_debug_segment() {
+  constexpr int argc = 3;
+  const char* argv[argc] = {"", "-fakeiso", "-debug-mem"};
+  exec_runtime(argc, const_cast<char**>(argv));
+}
+
 void createDirIfAbsent(const std::string& path) {
   if (!std::filesystem::is_directory(path) || !std::filesystem::exists(path)) {
     std::filesystem::create_directory(path);
diff --git a/test/goalc/framework/test_runner.h b/test/goalc/framework/test_runner.h
index d5fb13a4ba..63ec3bbc5c 100644
--- a/test/goalc/framework/test_runner.h
+++ b/test/goalc/framework/test_runner.h
@@ -41,6 +41,7 @@ struct CompilerTestRunner {
 
 void runtime_no_kernel();
 void runtime_with_kernel();
+void runtime_with_kernel_no_debug_segment();
 
 void createDirIfAbsent(const std::string& path);
 std::string getTemplateDir(const std::string& category);
diff --git a/test/goalc/test_game_no_debug.cpp b/test/goalc/test_game_no_debug.cpp
new file mode 100644
index 0000000000..331f4d4c8a
--- /dev/null
+++ b/test/goalc/test_game_no_debug.cpp
@@ -0,0 +1,32 @@
+// Test the game running without loading debug segments.
+
+#include "gtest/gtest.h"
+#include "goalc/compiler/Compiler.h"
+#include "test/goalc/framework/test_runner.h"
+
+TEST(GameNoDebugSegment, Init) {
+  Compiler compiler;
+  compiler.run_front_end_on_string("(build-kernel)");
+  std::thread runtime_thread = std::thread(GoalTest::runtime_with_kernel_no_debug_segment);
+
+  // this shouldn't crash
+  compiler.run_test_from_string("(inspect *kernel-context*)");
+
+  // these should be equal, both the fallback inspect method
+  EXPECT_TRUE(compiler.run_test_from_string(
+                  "(print (eq? (method kernel-context inspect) (method cpu-thread inspect))) 0") ==
+              std::vector<std::string>{"#t\n0\n"});
+
+  // should be below the debug heap.
+  EXPECT_TRUE(
+      compiler.run_test_from_string(
+          "(print (< (the uint (method kernel-context inspect)) (the uint (-> debug base)))) 0") ==
+      std::vector<std::string>{"#t\n0\n"});
+
+  // debug segment flag should be disabled.
+  EXPECT_TRUE(compiler.run_test_from_string("(print *debug-segment*) 0") ==
+              std::vector<std::string>{"#f\n0\n"});
+
+  compiler.shutdown_target();
+  runtime_thread.join();
+}
\ No newline at end of file