to fix the collision, you want to take samples along its line of movement, not just at the endpoint. that way the ball won't be able to pass through the paddles.
it's really, really hard to find a way to see where you need to put the blocks. I'd suggest adding transparency or somehow marking where the holes in the stack are.
 "AFITYG( Amazing find it yourself game)"){kind=icon}
 "Pong Clone"){kind=icon}
 "MAD: Mutually Assured Destruction"){kind=icon}
 "Super Crazy Guitar Maniac Deluxe 2"){kind=icon}
 "Sensou"){kind=icon}
 "Railz! LITE"){kind=icon}
 "STAR-Defence"){kind=icon}
 "The Tab Master"){kind=icon}
 "Fifty Five - Around the world: Vienna"){kind=icon}
 "5 Differences"){kind=icon}
 "Spin Cycle"){kind=icon}
 "Tetrical"){kind=icon}
 "Squarez"){kind=icon}
 "TargetBlaster"){kind=icon}
 "Falling Apple"){kind=icon}
 "9 Ball Connect"){kind=icon}
 "Target Practice"){kind=icon}
 "simple tetris"){kind=icon}
 "RBall+"){kind=icon}