Great concept for a co-op game.
I tried it with my kids today and they really liked it. :-)
Feedback regarding gamepad controls:
* More deadzone needed. When releasing the thumbstick the character sometimes moves.
* Move characters in thumbstick angle (not just 45 degrees).
(* Let how far you pull the thumbstick control the speed of characters. Not really needed but nice to have.)
With improved controls I'd definately use the game as a team exercise at work. :-)