Here is the full list of all 43 Override: Mech City Brawl achievements worth 1,000 gamerscore.
Defeated 500 Xenotypes
Defeated Malika's mech in the campaign
Met Malika in the campaign
Beat the campaign as Setesh
Beat the campaign
Traveled to the Moon in the campaign
Defeated the Flying-Shrimp Xenotype boss
Defeated the Muscle Xenotype boss
Defeated the Shaman Xenotype boss
Defeated 25 Xenotypes
Recruited by General Mavis
Completed the tutorial
Unlocked the "Infected" skin for all 12 starting mechs
Unlocked all skins for a mech
Unlocked an epic skin for each of the 12 starting mechs
Unlocked all accessories
Unlocked a total of 100 skins and accessories
Equipped your first accessory
In an online match, used Contessa's cursed hand ability to stop an incoming dive kick
Executed 30 Counter-Attacks
Knocked down 3 mechs with Cocada's wind ability in an online match
Absorbed a total of 500 damage with Setesh's pyramid ability in online matches
Won 5 online matches in a shared-mech
Won 5 online matches with each of the 12 starting mechs
Won an online match with each of the 12 starting mechs
In an online match, used Rocca's rocket punch to hit an enemy twice in a single attack
In an online match, used Shifu's ultimate on a blocking opponent
Used MetaGeckon's rolling ability 30 times in online matches
Won 50 online matches
Thrown Crystal's hammer to finish off a frozen opponent in an online match
In an online match, avoided 2 attacks with Mya's substitution without taking damage in between
Hit a total of 5 enemies with Pescado's ultimate chair shot in online matches
Won an online match with an ultimate attack as the final blow
As Vidar, trapped enemies 3 times in a single online match
Won an online match on every map
In an online match, used Vintage's teleport and got caught in an enemy's ultimate
Executed 10 Counter-Attacks
Using Watchbot, won an online 1v1 match in Japan without losing health
Won an online match without using any special abilities
Won your first online match with any mech
Won an online match without using your Ultimate ability
Won an online match without using any items
Unlocked your first random legendary skin