Well, this is a well constructed little game. Granted, with user intervention and not just the "I want 30 levels which require no thought, because I want my medals" user generated content, this could become a very big game.
From the user levels, I would hope two things. Firstly, that the levels are moderated and the really shitty one creature already in the box, so you win as soon as it's loaded levels get pruned out. Second, that there is some sort of "players pack" of the best levels launched, perhaps incorporating some sort of plot into the proceedings, where there is a Doctor Robotnik style character, that enjoys making little animals suffer and you're totally helpless.
Of course, it could be that a second version of the game would involve choice, making your progress entirely down to the discretion of the player. You could kill the creatures (easy) or save them (harder) on each level. Are you a corporate slave, or a hippie? Who knows, you might just be a corporate slave, but in that camp, because it's an easy life and you can play solitaire, while you should be working.
On the user generated content, you should be able to pick the sounds you creatures make when they die. There was one level I saw with a tune to it that would really benefit from this sort of thing, of course, that's abstract and a little sadistic, so I'll leave that thought hanging.
[Review Request Club]