I agree and the timing was pretty poor for that game. Windows Vista was JUST out the door and the graphics card drivers were downright terrible at the time, often crashing. Reason being Vista used a completely new driver model (WDDM).

I recall HGL also had some unfortunate memory leak issues.

In general I think that game was largely hamstrung by performance issues for one reason or another.

The idea of a FPS Action RPG like that wa as simple as it was brilliant. I've wondered why it hadn't been done before and still hasn't quite been done again. Games like Dark Souls exist but I don't think they're quite the same. Rumor is Diablo IV was going to go there but Blizzard later changed their mind, rather opting for a traditional isometric view. I think they lose a lot of immersion doing that. Imagine sneaking through damp, dark cellars and have demons lurk around the corners, and everything built upon a solid itemization system and replayability with randomized maps.