Here is the full list of all 40 Bitardia achievements.
The base game contains 37 achievements, and there is 1 DLC pack containing 3 achievements.
Rescue the hostage
Take the builder quest
You didn't accept the note-finding mission
Kill anons on the first mission
Get to jail after showing the video
Take the guard quest
Kill Cancer on the first mission
Pick Anon Mask
Finish the "QT 3.14" quest
Finish the "Hotline Bitardia" quest
Finish the "Fifth Column" quest
Finish a halloween-quests
Get arrested for spoiling the stand
Beat anon in cards
Take care of the hospital
Return anon's debt
Take care of the bank
You have finished the note-finding mission
Finish the "Winter is coming" quest
Agree to work on Abu
Break out of prison
Get to jail while taking the camera
Explode the building
Kill cancer on the first mission
Pick Cancer Mask
Get to jail after talking to police
Get to jail after entering the police station
Rob the caravan
Buy a pillow for anon
Get some cash on arena
More than 100 killed on arena
Served a term in prison
To die, refusing to work on the Abu
Finish the "Missing part" quest
Finish the "Fifth wheel" quest
Agree to work for resistance