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