I think moving the box around independently is pretty innovative feature. The control setup was very awkward since I wanted to move mouse (right hand) and arrow keys to move (right hand, can't use mouse same time....or if I use left hand on arrows then jump (spacebar) is not easily accessible. Moving character with WASD, jump space, mouse in right hand would likely be an improvement.
I was able to get pretty far just carrying the guy around on the first box...pretty far. But there is something that make the guy fall through the box (even falls through at the very start sometimes). Other times, after moving around and falling off box, the guy would no longer move with arrow keys at all.
Overall, the game idea is good and has some neat new mechanics.