There are quite a few differences that "aren't", meaning there are more than five on each level - annoying to have obvious differences not registering.
Half the levels complete themselves, the rest are so simple that it's really like clicking 'Continue' rather than taking a shot (and you really do only need one shot to complete the levels in which you're required to do something)
lvl5 - the ammo goes off the screen as the arm flies up and disappears, which somehow counts as a shot despite nothing being fired. I can't go any further in the game if I can't fire anything on lvl5...
 "MotoGP"){kind=icon}
 "Lose the TAIL"){kind=icon}
 "Shooting game"){kind=icon}
 "the pong game"){kind=icon}
 "CROSS IT"){kind=icon}
 "D-Finder 3"){kind=icon}
 "Domino Shemomino"){kind=icon}
 "LANANG ADVENTURE"){kind=icon}
 "BALLOON MASTER VER:1.0"){kind=icon}
 "Bouncy Ball Rider!"){kind=icon}
 "Crush the Castle"){kind=icon}