diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index eb25675d..97efdf8c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -72,7 +72,10 @@ additional guidelines:
 
 ## Demo Songs
 
-just put your demo song in `demos/`!
+just put your demo song in `demos/`! be noted there are some guidelines:
+
+- avoid Nintendo song covers.
+- avoid big label song covers.
 
 # Finishing