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