I enjoyed your game.
Admittedly, my first thought was negative toward the graphics (just the player and enemies) but after playing it, I think it's a total non-issue. Actually, I think what's smart about this, is that you didn't try to get too complicated with the graphics. You understand how much you know, and what you can do with programming, and you maximized your knowledge. You basically said, this is my box, these are my limitations, and you made it the best box you could. I really liked it.
That being said, I didn't know you could buy things, until reading the post above me. I knew I was collecting money and stuff, but I thought there'd be a time when the game prompted me to do that. Now that I know, and see how, it makes sense, but I got 3rd on the leaderboard without ever knowing that.
Anyway, great job. I also particularly liked how it went into slow motion when you die.
I'll be interested to see how this game evolves. Keep up the good work.