Pinball Sniper - I've increased my top score to 566 which places me 82 out of 803,855. That achievement, and $2.75, gets me a ride on the subway.
Double Juggle - I've increased my score to almost 150.
Maze 11 - I've completed all but 2 levels in the 6x6 series. I think they may be impossible, but it's virtually impossible to contact the developer.