High score was exactly 3000! You can easily implement online leaderboards with lootlocker.com. Just saying :)
I liked the presentation a lot- keeping everything black and white, and only using color to make the enemies stand out is a solid choice and makes the game look stylish. Music and retro-sounds add to that.
Gameplay is interesting. Really simple to learn, but there's depth to it, that you can see the longer you play. Upgrades area nice touch, but it feels like I mostly used them to recover health :)
As for the theme... well, the level space is limited by walls, but that's kinda it. I think you could have done more in that regard.
Over all- really fun, really stylish! Keep up the good work!