Here is the full list of all 18 OTXO achievements.
Play fetch
Collect all guns
Destroy the Heart
Collect everything from the gachapon machines
Vault over 50 times
Kill 50 enemies with grenades
Kill an enemy with a thrown magazine
Kill 15 enemies with doors without dying
Order the ANIMAL drink at the bar
Clear a room by only kicking
Kill 50 enemies with kunai
Roll over 100 times
Clear a room without using Focus
Die for the first time
Go fishing
Clear a run on Impossible Mode
Unlock all drinks
Clear a full run without taking any drinks