I had fun with this! I see a ton of potencial on this game, but i spot problems during the gameplay that could be resolved:
*Sometimes when you Grow up back you can clip through things.
*There's lack of feedback while shooting enemies, a simple sound or effect could make the difference to make you feel you killing them for real, you shoot them but it feels like don't at times. However the Ambient of the enemies is very disturbing :S!
*There's a weird bug where if you click Restart and try to pick up a cube you can't anymore, very interesting.
I want to say, it is a very good game! With these 3 problems solved your game is going to be at the next level! Keep this great work guys :D