Well for a 8 bits song its pretty cool, try not to always keep the same notes so it doesn't feel so repetitive, you can try adding counterpoint melodies
Or also ear-candy stuff. (Small arrangements with musical notes or effects that enrich the music [̲̅$̲̅(̲̅ ͡ಠ_ಠ)̲̅$̲̅] sounds awesome!