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