Neat game! The fact that you imposed on yourself the extra restriction of using no prefabs and no materials is darn impressive :)
I will say that the game is a bit tricky, I haven't managed to get past the second level as of yet, but it's pretty entertaining to play and the idea of losing an ability after each level fits the theme rather well.
One thing that I found unclear was the shooting; I didn't realize at first that the sumo-ers were taking damage, even tough they were animating, because there weren't any bullets getting spawned, so I was assuming it wasn't working. Only later did I figure out that if I hold it down long enough they eventually die/get pushed off, and from there on, the gun felt a bit op (tough apparently still not enough to get my fat ass to the last level :D)