Here is the full list of all 27 Gear Up achievements.
Destroy 10 enemies with the default starter cannon.
Drown in the water at least once.
Destroy 1500 enemies
Win 20 deathmatch rounds.
Win 3 conquest rounds.
Win 20 conquest rounds.
Win a TDM round overwhelmingly, with a ratio of 4:1 or higher.
Win a Conquest round overwhelmingly, with a ratio of 4:1 or higher.
Capture a conquest tower together with 3 or more teammates.
Recieve 500 damage without being destroyed in a round.
Assist in capturing at least 20 conquest towers in a single round.
Repair 30000 armor in lifetime.
Repair (1250) armor in one round of a team game mode.
Back playing after more than one week of Gear Up absence.
Win 20 team deathmatch rounds.
10 kills in a row
Killed a deserting enemy
Destroy 100 enemies
6 kills in a row
Destroy 75 enemies
Destroy 50 enemies
Destroy at least seven different opponents in a team game mode.
4 kills in a row
Destroy 25 enemies
3 kills in a row
2 kills in a row
Destroy 20 enemies with the Grayhound (saws).