The following avatars can all be gained from playing games.

Score over 1,000 in Addow Ride.
Kill at least one enemy and send score in Battle of Baspinar.
Score over 100 in Biala Tetris.
Score over 75 in Bounchy.
Score over 1000 and send score in Candy Cannon.
Score over 300 on Dukka Trove
Score over 75 on Fruit Harvest.
Score over 3000 points on Marapets Keeper.
Random when playing Murfin Chase.
Play Oglue Lunch and send score when it is game of the week.
Score over 50,000 when playing Phanty Rescue.
Win a Bonus Game Prize when playing Protect The Egg.
Play Rofling Gold when it's the featured Game of the Day.
Play Shoot the Fatty. Shoot one fatty and let the time run out. Send score.
Complete a game of Sudoku .
Random when sending score on Undead Billiards.
Send score 3 times on Yakubi Attack then go back to the game.