Cool concept, but man I wanted to be able to move backward to save myself if I overstepped. Once you make a small mistake, you see your demise coming and even if you have time to react there's nothing to be done (enemies are too high to be shot at, but low enough to collide with you still). Either a faster moving player, or ability to backstep would provide some counterplay to this....
Once I finally reached the end I wanted to try a new level, or something a little faster. This is a good base concept, left me wanting more to play.