Here is the full list of all 21 Pizza Titan Ultra achievements.
Complete Chapter 2
Get a bronze challenge trophy
Complete How To Play
Repaint mech
Get 3 silver challenge trophies
Get 8 bronze challenge trophies
Get a gold challenge trophy
Get 4 gold challenge trophies
Get 8 gold challenge trophies
Collect $10K
Collect $100K
Complete Chapter 8
Complete Chapter 12
Complete Chapter 15
Complete Chapter 21
Complete Chapter 24
Unlock a costume part
Unlock all 80 costume parts
Unlock an Ultra Ability
Unlock 4 Ultra Abilities
Collect $500k