Here is the full list of all 12 Geometry Wars: Retro Evolved² achievements worth 200 gamerscore.
2, 4, 11, 15, 17, 18 and 19.
Reach the end of sequence.
Score at least 1,000,000 points in all single player modes.
Unlock all game modes.
Score 1,000 points in Waves without collecting any geoms.
Dodge 8 lines of enemies in Waves without firing a shot, or destroying any enemies.
Chain together 5 gates in 5 seconds. Crossing at least one gate every second.
Perform the Wax On achievement twice in a single game, don't forget to breathe.
Rub your ship along all four arena walls in Pacifism.
Activate 30 zones in King without firing a shot, or destroying any enemies.
Destroy 75 enemies in a game of Deadline using bullets bounced off of gates.
Collect 500 geoms in a single game.