diff --git a/configure.ac b/configure.ac
index ae1320b..3299252 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,7 +26,7 @@ OPT_LEVEL=3
 if test "$GCC" = "yes"
 then
         WARNINGS="-Wall -Wdeclaration-after-statement -Wredundant-decls"
-        CFLAGS="-O$OPT_LEVEL -g $WARNINGS $orig_CFLAGS"
+        CFLAGS="-O$OPT_LEVEL $WARNINGS $orig_CFLAGS"
 fi
 
 # PKG_CHECK_MODULES(SDL, [sdl2 >= 2.0.7])
@@ -115,7 +115,7 @@ AS_IF([test "x$with_libpng" != xno], [
 
 # TODO: We currently link everything against libraries that don't need it.
 # Use the specific library CFLAGS/LIBS variables instead of setting them here.
-EMFLAGS="-gsource-map -s INVOKE_RUN=1 -s USE_SDL=2 -s USE_SDL_MIXER=2 -s LEGACY_GL_EMULATION=0 -s USE_SDL_NET=2 -s ASSERTIONS=0 -s WASM=1 -s ALLOW_MEMORY_GROWTH=0 -s FORCE_FILESYSTEM=1 -s EXTRA_EXPORTED_RUNTIME_METHODS=[['FS','ccall']] -s SAFE_HEAP=1 -s EXIT_RUNTIME=1 -s STACK_OVERFLOW_CHECK=1 -s PROXY_POSIX_SOCKETS=0 -s USE_PTHREADS=0 -s PROXY_TO_PTHREAD=0 -s TOTAL_MEMORY=64MB -s ERROR_ON_UNDEFINED_SYMBOLS=0 -s ASYNCIFY -O3 --source-map-base /"
+EMFLAGS="-s INVOKE_RUN=1 -s USE_SDL=2 -s USE_SDL_MIXER=2 -s LEGACY_GL_EMULATION=0 -s USE_SDL_NET=2 -s ASSERTIONS=0 -s WASM=1 -s ALLOW_MEMORY_GROWTH=0 -s FORCE_FILESYSTEM=1 -s EXTRA_EXPORTED_RUNTIME_METHODS=[['FS','ccall']] -s SAFE_HEAP=0 -s EXIT_RUNTIME=1 -s STACK_OVERFLOW_CHECK=0 -s PROXY_POSIX_SOCKETS=0 -s USE_PTHREADS=0 -s PROXY_TO_PTHREAD=0 -s TOTAL_MEMORY=64MB -s ERROR_ON_UNDEFINED_SYMBOLS=0 -s ASYNCIFY -O3"
 
 CFLAGS="$CFLAGS $SDL_CFLAGS ${SAMPLERATE_CFLAGS:-} ${PNG_CFLAGS:-} $EMFLAGS"
 LDFLAGS="$LDFLAGS $SDL_LIBS ${SAMPLERATE_LIBS:-} ${PNG_LIBS:-} $EMFLAGS -lwebsocket.js"
diff --git a/src/doom/d_main.c b/src/doom/d_main.c
index 9a462e2..3178ee1 100644
--- a/src/doom/d_main.c
+++ b/src/doom/d_main.c
@@ -1683,13 +1683,15 @@ void D_DoomMain(void)
     if (p) {
         singledemo = true; // quit after one demo
         G_DeferedPlayDemo(demolumpname);
-        D_DoomLoop(); // never returns
+        D_DoomLoop(); // returns under Emscripten, so stop here
+        return;
     }
 
     p = M_CheckParmWithArgs("-timedemo", 1);
     if (p) {
         G_TimeDemo(demolumpname);
-        D_DoomLoop(); // never returns
+        D_DoomLoop(); // returns under Emscripten, so stop here
+        return;
     }
 
     if (startloadgame >= 0) {