Hey, a fellow local multiplayer submission! (Although ours is competitive, not co-op.) I really like this concept as a co-op game that's about communication and coordination. A bit like a multiplayer-QWOP. I think it needs a fair bit of polish to be playable though.
Currently, the main issue is that it's really hard to stay on top of who can do what. You constantly have to monitor the text panels in the corners, which takes attention away from the main game. We actually had the exact same problem in our game (the steering wheels initially were in the corners of the screen), so we ended up moving them right where the action is, so there's only one place to look at. That could be a bit hard for this game, although you could make the character considerably larger and then use coloured body parts to indicate who can do what. Alternatively, have an obvious countdown and let the screen flash when the controls change, so you can't easily miss it and know when you need to shift gears.
Anyway, I think with a little redesign of the UI, this could be a really fun and addictive co-op experience, since the core idea seems pretty solid. :)