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