If You complete the indicated task You'll get the allotted gamerscore.
All 3's Guru (40) - Get 36 points 3 times (when playing All 3's game with double 9 domino set).
Mega Player (25) - Win 5 rounds in a row.
Perfect Game (20) - Win a game without drawing.
Guru Beater (20) - Win 40 games against Guru AI(s).
Domino Explorer (15) - Win a game in all game modes at least once in both Single Player and Multiplayer modes.
Doubles (15) - Win at least 1 round with at least 1 of each double placed last.
Beat the Masters (15) - Win 10 games against Master level AI(s).
Super Blocker (10) - Win 30 blocked rounds.
All 3's Winner (10) - Win 30 All 3's games.
All 5's Winner (10) - Win 50 All 5's games.
Real Win (10) - Win a multi-player game.
First Win (10) - Win a game in single player.