One problem with a lot of modern games is just how big they're getting, but HELLDIVERS 2 is about to massively shrink thanks to work behind the scenes. In a news post on Steam the developers at Arrowhead Game Studios noted they pulled in Nixxes to help get it sorted.

They were making small changes across a few patches, but now the big stuff is here and you can try it out in a Steam Beta via the "prod_slim" branch. Right click the game, go to Properties -> Beta and select "prod_slim" from the drop-down box. The result should be a reduction in installation size from "~154GB to ~23GB". What an insane difference.