Cool game! Really well executed, I didn't find any bugs or anything. Nice music, too ^^
I think at the harder difficulties it might be a bit too much to focus on; remembering words and working out the antonyms at such speed, whilst frequently shifting focus from one board to the other.
It would be awesome if the blocks didn't disappear until landing! this would mean you could set up chains, where finding a match would make blocks above fall down, to find another match.
A great entry, though. Well done!