Here is the full list of all 23 Deformers achievements.
Get 50 Kills
Earn your first Prestige rank
Kill an enemy using the pit in the center of Big Top
Level up!
Score a Hat Trick in Form Ball
Score a goal in Form Ball
Kill an enemy while you're cloaked
Complete an online match
Complete a match online in Splitscreen
Get 100 Kills
Get 250 Kills
Get 500 Kills
Get 5 kills with a single Rampage
Reach Level 10
Reach Level 20
Reach Silver ranking in Prestige
Reach Gold ranking in Prestige
Score 25 goals in Form Ball
Score 50 goals in Form Ball
Get 15 Assists in Form Ball
Get 10 Saves in Form Ball
Break 100 stacks
Consume 5000 pieces of debris (including gibs)