diff --git a/Makefile b/Makefile
index 928cd4c..90f6451 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 .ONESHELL:
 
 CC=gcc
+O=2
 CFLAGS=-lcsfml-window -lcsfml-system -lcsfml-graphics
 PREFIX=$(HOME)/.local
 
@@ -12,7 +13,7 @@ clean:
 
 ls7emulator:
 	cd src
-	$(CC) main.c -o ls7emulator $(CFLAGS) -O2
+	$(CC) main.c -o ls7emulator $(CFLAGS) -O$(O)
 
 	rm ../bin -rf
 	mkdir ../bin