The enemies movement for some reason remind me about the nokia game "BOUNCE", and i love the minimal style within the game, plus the color pallette you chose for this game was also good.
BUT the enemies collision box should be a little bit small as i think they appear to be bigger than their sprite size, and the enemies present after the yellow gate is opened either their number or their speed needs to be decreased,as i tried multiple time to get pass through them, but my player speed was too slow to get through them.