Okay idea. It's got some rough edges.
There are alot of things that need to be fixed with this game. It seems like a novice effort. You need to polish it more.
1) The enemies aren't affected by the walls (except for the one that's killed by the walls)
2) You have to hit the reset button after you die. How hard would it have been to fix that?
3) After the guy dies you can still push him around with the line an finish the level.
4) The levels where you can't draw are just crappy one-screen platformers.
5) Bad collision detecting, specifically with the falling spikes and crawling snakes.
It just looks like you found a code to draw with the mouse and then said, "I'm making a game out of this!"
It's not horrible, mind you. It just needs some polishing. The music was good, and fit the mood.