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