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