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