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