I was curious if they optimized the download. Did it download the 'optimized' ~150 GB and wasting a lot of time there or did it download the ~20 GB unique data and duplicated as part of the installation.

I still don't know but found instead an interesting reddit post were users found and analyzed this "waste of space" three month ago.

https://www.reddit.com/r/Helldivers/comments/1mw3qcx/why_the...

PS: just found it. According to this Steam discussion it does not download the duplicate data and back then it only blew up to ~70 GB.

https://steamcommunity.com/app/553850/discussions/0/43725019...