Blame HDDs.

Helldivers 2 developer Arrowhead Studios still doesn't have a solution for the shooter's groaning installation size on PC — but it is working on it.
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Helldivers 2’s PC Bloat Explained: Mechanical Hard Drives Are the Culprit and There’s No Quick Fix Yet

Helldivers 2 devs explain why PC installation hits 150GB while consoles need just 50GB and reveal their multi-tier fix ...