Here is the full list of all 23 Afterparty achievements.
Intentionally lose to Satan.
Intentionally curse twenty times.
Recruit the Drunk Idiot Demon for Satan's final challenge.
Make friends with Sam.
Reunite Milo and Lola.
Play as Milo after fighting with Lola.
Get Apollyon's Seal of Approval.
Try 20 different drink types.
Get Asmodeus's Seal of Approval.
Don't miss a step while dancing.
Get an Invite to Satan's from Fela.
Kick off your adventure in Hell.
Get an Invite to Satan's from Lynda.
Play as Lola after fighting with Milo.
Fail to beat Satan.
Beat Satan and earn your way back home.
Make friends with Wormhorn.
Reunite Beth and Asmodeus.
Play a perfect game of beer pong.
Play a perfect stacking game.
Drink a lot of booze.
Waste 20 minutes on Bicker.
Pet the damn dog.