diff -ruN os-orig/src/core/audio.c os/src/core/audio.c
--- os-orig/src/core/audio.c
+++ os/src/core/audio.c
@@ -127,7 +127,14 @@
         m = mallocx(sizeof *m);
         m->is_paused = false;
         m->filepath = str_dup(path);
-        if(NULL == (m->stream = al_load_audio_stream(fullpath, 4, 1024)))
+#if defined(__EMSCRIPTEN__)
+        /* no feeder threads in the browser: the streams are refilled from the audio
+           callback, so they get bigger buffers */
+        m->stream = al_load_audio_stream(fullpath, 8, 4096);
+#else
+        m->stream = al_load_audio_stream(fullpath, 4, 1024);
+#endif
+        if(NULL == m->stream)
             fatal_error("Can't load music \"%s\"", path);
         
         /* configure the audio stream */
diff -ruN os-orig/src/scenes/gameover.c os/src/scenes/gameover.c
--- os-orig/src/scenes/gameover.c
+++ os/src/scenes/gameover.c
@@ -101,7 +101,7 @@
     mobilegamepad_fadeout();
 
     /* fade out */
-    if(gameover_timer >= GAMEOVER_APPEARTIME && !music_is_playing(music)) {
+    if(gameover_timer >= GAMEOVER_APPEARTIME && !music_is_playing()) {
         if(fadefx_is_over()) {
             quest_abort();
             scenestack_pop();
diff -ruN os-orig/src/scripting/loaderthread.c os/src/scripting/loaderthread.c
--- os-orig/src/scripting/loaderthread.c
+++ os/src/scripting/loaderthread.c
@@ -60,10 +60,16 @@
             ctx->argv[i] = str_dup(argv[i]);
     }
 
+#if defined(__EMSCRIPTEN__)
+    /* the browser build has no threads: load the scripts right now. The "thread"
+       handle is the context itself, which surgescriptloaderthread_destroy() returns */
+    return (ALLEGRO_THREAD*)load_surgescript(NULL, ctx);
+#else
     /* create & start thread */
     ALLEGRO_THREAD* thread = al_create_thread(load_surgescript, ctx);
     al_start_thread(thread);
     return thread;
+#endif
 }
 
 /*
@@ -75,6 +81,11 @@
 {
     ssthreadcontext_t* ctx = NULL;
 
+#if defined(__EMSCRIPTEN__)
+    /* already loaded by surgescriptloaderthread_create() */
+    ctx = (ssthreadcontext_t*)thread;
+    assertx(ctx != NULL);
+#else
     /* wait for completion */
     void* ret = NULL;
     al_join_thread(thread, &ret);
@@ -83,6 +94,7 @@
 
     /* release thread */
     al_destroy_thread(thread);
+#endif
 
     /* error checking */
     if(ctx->error_message[0] != '\0') {
diff -ruN os-orig/src/scripting/music.c os/src/scripting/music.c
--- os-orig/src/scripting/music.c
+++ os/src/scripting/music.c
@@ -136,7 +136,7 @@
 
     if(music != NULL) {
         if(music_current() == music && music_is_paused())
-            music_resume(music);
+            music_resume();
         else
             music_play(music, false);
         music_set_volume(volume);
diff -ruN os-orig/src/core/video.c os/src/core/video.c
--- os-orig/src/core/video.c
+++ os/src/core/video.c
@@ -381,10 +381,16 @@
 
     /* clearing just after flipping may provide a slight performance increase
        in some drivers */
+#if defined(__EMSCRIPTEN__)
+    /* in the browser the flip does not present anything: the frame is shown when the
+       main loop gives control back to the page. Clearing the display now would wipe the
+       frame that is about to be shown (a black screen). The next frame covers it all. */
+#else
     if(_glClear != NULL)
         _glClear(GL_COLOR_BUFFER_BIT);
     else
         al_clear_to_color(al_map_rgba_f(0.0f, 0.0f, 0.0f, 0.0f));
+#endif
 
 #if USE_ROUNDROBIN_BACKBUFFER
     /* use a round-robin scheme for a (possible) performance improvement,