I love the underwater theming, and there's a lot of good juice to your game.  It's well-designed, well-programmed, the music is great, and most importantly, it's fun. The wall tiles and quite a bit of the graphics clash with the type of artstyle you're going for though, so I hope that gets touched up on in the future. I also feel like the Boost UI could be changed so it appears above or around the player, since this game is faster paced. Excellent work!