All bow to heavy metal, Size matters, Damsel in distress.
These are story missions.
Space Pirate, Straight Edge.
In the bar in Act 2, you come across 2 bottles of Nom Juice before the Disco Inferno mini-boss. Shoot them, pause, and restart checkpoint (make sure you went inside the door and triggered the checkpoint first!). Keep doing that, then drink them, pause, and restart the checkpoint. Twenty bottles of each later, and you’re 20 GS richer.
Once you kill that miniboss, stay on the dance floor and leash the enemies into the electric signs for shockers. Stay up there until this achievement pops (kill all enemies without leaving the dance floor). If you don’t get it, start over from checkpoint and try, try again.
25% skillshots complete. Still pretty much random.