diff --git a/Makefile.libretro b/Makefile.libretro
index ed92c27..58db740 100644
--- a/Makefile.libretro
+++ b/Makefile.libretro
@@ -772,9 +772,14 @@ ifneq (,$(findstring msvc,$(platform)))
    CFLAGS   += -MT
    CXXFLAGS += -MT
 endif
+ifeq ($(platform), emscripten)
+   CFLAGS   += -O3 -DNDEBUG
+   CXXFLAGS += -O3 -DNDEBUG
+else
    CFLAGS   += -O2 -DNDEBUG
    CXXFLAGS += -O2 -DNDEBUG
 endif
+endif
 
 ifeq ($(SHARED_LIBVORBIS),)
    TREMOR_SRC_DIR := $(CORE_DIR)/core/tremor