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