diff --git a/crates/asset_transport/src/discover.rs b/crates/asset_transport/src/discover.rs
index c715197..cf35515 100644
--- a/crates/asset_transport/src/discover.rs
+++ b/crates/asset_transport/src/discover.rs
@@ -250,6 +250,28 @@ fn game_files(root: &Path) -> impl Iterator<Item = Result<PathBuf, String>> {
     files_under(search_roots(root))
 }
 
+/// Folders the game never keeps zones in: cargo's output when the games root is the build's own
+/// `target/play` (tens of thousands of files, walked on every discovery), and our own
+/// artifacts.
+const NOT_GAME_DIRS: [&str; 6] = [
+    "incremental",
+    "deps",
+    "build",
+    ".fingerprint",
+    "examples",
+    "iw4l-artifacts",
+];
+
+fn is_not_game_dir(path: &Path) -> bool {
+    path.file_name()
+        .and_then(|name| name.to_str())
+        .is_some_and(|name| {
+            NOT_GAME_DIRS
+                .iter()
+                .any(|skip| name.eq_ignore_ascii_case(skip))
+        })
+}
+
 fn files_under(roots: Vec<PathBuf>) -> impl Iterator<Item = Result<PathBuf, String>> {
     let mut pending: VecDeque<_> = roots.into_iter().map(Ok).collect();
     let mut visited = HashSet::new();
@@ -259,6 +281,9 @@ fn files_under(roots: Vec<PathBuf>) -> impl Iterator<Item = Result<PathBuf, Stri
                 Ok(path) => path,
                 Err(error) => return Some(Err(error)),
             };
+            if is_not_game_dir(&path) {
+                continue;
+            }
             let canonical = match std::fs::canonicalize(&path) {
                 Ok(path) => path,
                 Err(error) => {