wow nice game, it's really fun ! There is a good game feel! Abilities are cool (I especially like timestop ability). Animations and graphics are nice, all enemies and bullets are visible (very important in this game genre).
I think the player could be a bit faster (you could increase his acceleration). Collision with box isn't precise (we can't pass between 2 boxes). But, my real regret is the lack of sound effects, it could be very useful to improve the game feel !
Anyway, it's a really a good and FUN game ! Nice job !