I expect it's a story that'll never get told in
enough detail to satisfy curiosity, but it certainly
seems strange from the outside for this optimisation
to be both possible and acceptable.
From a technical perspective, the key thing to know is that the console install size for HD2 was always that small -- their build process assumed SSD on console so it didn't duplicate stuff.
154GB was the product of massive asset duplication, as opposed 23GB being the product of an optimization miracle. :)
How did it get so bad on PC?
Well, it wasn't always so crazy. I remember it being reasonable closer to launch (almost 2 years ago) and more like ~40-60GB. Since then, the devs have been busy. There has been a LOT of reworking and a lot of new content, and the PC install size grew gradually rather than suddenly.
This was probably impacted to some extent by the discontinued game engine they're using. Bitsquid/Stingray was discontinued partway through HD2 development and they continued on with it rather than restarting production entirely.
154GB was the product of massive asset duplication, as opposed 23GB being the product of an optimization miracle. :)
How did it get so bad on PC?
Well, it wasn't always so crazy. I remember it being reasonable closer to launch (almost 2 years ago) and more like ~40-60GB. Since then, the devs have been busy. There has been a LOT of reworking and a lot of new content, and the PC install size grew gradually rather than suddenly.
This was probably impacted to some extent by the discontinued game engine they're using. Bitsquid/Stingray was discontinued partway through HD2 development and they continued on with it rather than restarting production entirely.
https://en.wikipedia.org/wiki/Bitsquid