Great work! This game feels really fresh, and the final level had me smiling and laughing involuntarily as I kept getting surprise attacks from distant blocks taht I though I was don with.
One comment in terms of design - I think it would make sense to have some sort of UI indication to how many boxes should be connected to the player to pass. Trial and error would definitely solve it, but I think some indication would prevent some confusion or needless frustration for at least some players.
Hope to see this fleshed out into a full game someday =)