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