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