Starting on the second level some of the flying elves can shoot at you. Those aren't created randomly.
The flying elves that can't shoot are created randomly to keep you on your toes while you're trying to get through the obstacles. None of the other enemies are created randomly. (the definition of "random" may not be quite the way to describe how the non-shooting elves appear anyway. there's a very specific formula.)
The third level implements exploding Christmas presents and an end boss. I've played through the game successfully at least 20 times to make sure there's always a way to win.
I would recommend playing through the entire game if you haven't. I think you may find it very rewarding. Either that or you'll be really frustrated you actually played the whole thing depending on how long it takes you.
Basically I wanted to capture the difficulty of games like Gradius and Contra (after you beat a game like that you feel like you've accomplished something). I very much appreciate the constructive criticism. It'll probably make my next game a lot better.
Also, thanks to everyone who commented or downloaded the game! Comment edited by Allen Johnson on 6/15/2008