Here is the full list of all 50 Ultra Savage achievements.
Reach Level 200
Defeat Unlimited Nightmare Error
Have Over 10'000'000 HP
Defeat Unlimited Error
Defeat Dr. Congo
Defeat Error
Enhanced Item +20
Defeat Githeon The Galactic Conqueror
Defeat Oreb and Zeeb
Reach Level 180
Defeat Xoreb
Deal Over 10'000'000 Damage
Reach Level 160
Reach Level 140
Have Over 1'000'000 HP
Defeat Nahash
Enhanced Item +10
Do Ten Time Travels
Deal Over 1'000'000 Damage
Defeat King Bera the Reaper
Made A Costume
Defeat Lord Pretty Face Coolinagi
Have Over 300% ATK SPD
Do Six Time Travels
Reach Level 100
Reach Level 80
Have Over 100,000 HP
Enhanced Item +6
Have Over 100 CHI
Defeat Raki-Raki The Demolisher
Maxed Out A Skill
Deal Over 100'000 Damage
Have Over 50% CRIT
Defeat Liki Lee The Amgi-Turner
Do Your Second Time Travel
Reach Level 60
Deal Over 9'000 Damage
Do Your First Time Travel
Enhanced Item +3
First Enhancement
Defeat Heli Boss
Have Over 150% ATK SPD
Reach Fusion Level 10
Deal Over 1'00 Damage
Reach Level 30
Defeat Prince of Madness
Reach Level 10
Equip a blade and meet Kairon
Do your first fusion
Have over 3'00 HP