Nice overall effort. I think the beat you chose might not really fit the whole chiptune thing when we're talking about games. Nice melody, but your sound samples are similar and in the same tonal area or octave if you will, which makes things pretty hectic at some points resulting in a not clear tune. The melodies are mighty fine but you should try to make it more coherent and clear to one's ear. Try changing octaves when things get wild in order to keep it discernible.