Here is the full list of all 26 Priest Simulator achievements.
Clean all the scribbles
Collect all the relics
Collect all the pictures
Collect the Vulgators
Do all the sermons
Renovate the church
Let the love win
Rescue Melissa
Eat a cake
Be a coach
Show off at the casino
Check out the other side
Beat the required time on all exorcisms
Do the funeral
Collect the codexes
Rescue Bropol Extravaganza
Take part in an exorcism
Talk to Nostramadus
Defeat Hoho
Rescue Torpedo
Clean it up
Serve well
Leave no cross ununturned
Answer the phone
Defeat Bebok
Turn it on