diff --git a/Makefile b/Makefile
index 1294d2f..1c86c08 100644
ifeq ($(DEBUG),1)
FLAGS += -O0 -g
else
-FLAGS += -O2 -DNDEBUG
+ifeq ($(platform), emscripten)
+ FLAGS += -O3 -DNDEBUG
+else
+ FLAGS += -O2 -DNDEBUG
+endif
endif
ifeq (,$(findstring msvc,$(platform)))