How to earn Game Over achievement / trophy
Play the game main story (specifically Charlie's leads) until you can interact with 2-BIT inside Charlie's Mansion.
Head to Updaam Noon and sneak in to Condition Detachment. I like to go around the right hand side of Charlie's Mansion with upgraded Shift Slab and the Double Jump trinket. You should be able to shift across the rocks then around to the back of the building. Look up and Shift up to the walk way. Then jump or Shift to the wooden door and then 2-Bit's door will be right in front of you (it needs Hacking to open).
Make sure to get to 2-BIT unnoticed. If Charlie is spooked this will not work.
Interact with 2-BIT and tell it to set Charlie as the Invader.
Within a few seconds Eternalists will begin attacking him. And that should be it!