Here is the full list of all 21 Holo X Break achievements.
Complete all achievements.
Watch the credits to the end.
Clear a run in 50 minutes.
Defeat a boss without ever being knocked down.
Clear a run without spending any HoloCoins at all.
Reach a 30 KO-Chain.
Earn more than 100,000 subscribers
Apply FROZEN, BURN, and POISON on 1 enemy.
Unlock 100 emotes.
Fill out the entire equipment inventory.
Unlock 50 emotes.
Clear Hard Mode.
Fill all 5 slots of inventory with only Healing items.
Enhance a Rare equipment into S. Rare
Clear a run with less than 100 dislikes.
Clear Story Mode.
Upgrade an equipment to level 15.
Reach 50 in one stat.
Wear a full set of S.Rare equipment.
Save Ollie.
Bring 5+ Followers into a boss fight.