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