You need a pretty decent computer to handle all the pixels. If there was a option to..reduce the particles from the explosions, then it wouldn't be bad.
level 20 isn't that hard...
It's easy getting through the top without getting hit. Just let the cannon's balls hit you from the bottom, you won't get hit.
then wait until the 1 spike moves >>>
and the the other one moves down. Take 2 ammo to knock the cannon out. Knock a block into the guy's balloons to recgonize you, now just stay behind the walls as the enemy and cannons blast them away trying to hit you. Then knock the guy out. You'll need to get ammo if you want to collect coin.
wow guys just because u guys suck and can't beat certain levels, don't mean you should give it a bad rating. being hard = a good thing cause it's a challenge. >_>