diff --git a/emscripten/preamble.js b/emscripten/preamble.js
index da24e4c9..5e7c7ee0 100644
--- a/emscripten/preamble.js
+++ b/emscripten/preamble.js
@@ -23,12 +23,16 @@ glContext.getSupportedExtensions().forEach(function(ext) {
 
 function SyncFS(is_load, ccptr) {
     FS.syncfs(is_load, function(err) {
-        Module['ccall'](
-            'vfs_sync_callback',
-            null, ["boolean", "string", "number"],
-            [is_load, err, ccptr],
-            { async: true }
-        );
+        // wasmga.me: without IndexedDB this calls back at once, while the
+        // game is still on the stack; go back to the game from a fresh stack.
+        setTimeout(function() {
+            Module['ccall'](
+                'vfs_sync_callback',
+                null, ["boolean", "string", "number"],
+                [is_load, err, ccptr],
+                { async: true }
+            );
+        }, 0);
     });
 }
 
@@ -39,3 +43,16 @@ if(typeof dynCall === 'undefined') {
 };
 
 var debug_tables;  // closure may fail on debug builds without this
+
+// wasmga.me: the play page reaches the file system through these (closure
+// renames FS's own methods). It writes the game files to /res-cache and keeps
+// the player's files in /persistent/storage itself, so IndexedDB isn't used.
+Module['wgFS'] = {
+    'mkdirTree': function(path) { FS.mkdirTree(path); },
+    'writeFile': function(path, data) { FS.writeFile(path, data, { canOwn: true }); },
+    'readFile': function(path) { return FS.readFile(path); },
+    'readdir': function(path) { return FS.readdir(path); },
+    'exists': function(path) { return FS.analyzePath(path).exists; },
+    'isDir': function(path) { return FS.isDir(FS.stat(path).mode); },
+    'mtime': function(path) { return FS.stat(path).mtime.getTime(); },
+};
diff --git a/src/vfs/emscripten_fetch.c b/src/vfs/emscripten_fetch.c
index 1b88da11..41ba20a0 100644
--- a/src/vfs/emscripten_fetch.c
+++ b/src/vfs/emscripten_fetch.c
@@ -19,7 +19,9 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#define CACHE_PATH "/persistent/res-cache"
+// wasmga.me: the play page writes game files here (in memory) as its data
+// zips arrive, so nothing is downloaded file by file or kept in IndexedDB.
+#define CACHE_PATH "/res-cache"
 #define MAX_PREFETCH_REQUESTS 4
 
 #define MAKE_CACHED_PATH(_var_name, _content_id) \
@@ -48,6 +50,7 @@ EM_JS(void, update_dl_status, (int done, int total), {
 });
 
 static void prefetch_next(FetchFSContext *ctx) {
+	return;  // wasmga.me: the play page downloads the data
 	while(ctx->requests.num_elements_occupied < MAX_PREFETCH_REQUESTS) {
 		update_dl_status(ctx->prefetch_iter, resindex_num_file_entries());
 
@@ -145,6 +148,12 @@ static SDL_IOStream *vfs_fetch_open(VFSResIndexFSContext *resindex_ctx, const ch
 		return cached_rw;
 	}
 
+	// wasmga.me: wait for the play page to write the file
+	while(!(cached_rw = SDL_IOFromFile(cached_path, "r"))) {
+		emscripten_sleep(10);
+	}
+	return cached_rw;
+
 	for(;;) {
 		fetch = fetch_begin_request(ctx, content_id);
 		fetch_wait(fetch);