http://www.animenewsnetwork.com/encyclopedia/anime.php?id=497

Turns out that this one was adapted into a movie way back when, I haven't heard anything good about the movie, but the game looks like it could be some awesome Quake II-like fun.

It is! :)

When SIN came out, every one predicted it to be the GOTY that year. Then out of nowhere came Half Life and sniped it.
The (quirky/bizarre) creativity that went into SIN is amazing, way above Quake 2. But can be hard as hell, esp. the Bossfight but still be fun.

PS: did happily shell out the $10! and I already have the Steam Version and the (dead) old Mac Retail Version.

Quake 2 was very boring!

...but that soundtrack by Sonic Mayhem seriously made the game!

Zak Belica's soundtrack in SiN is even better.

Yeah, saw this movie quite a while back. I think I still have it on a CD somewhere. While this movie is not an exception to the rule that movie adaptations of video games never yield good results, I nontheless found it quite enjoyable, though quite over-the-top when compared with the game. I might get around to watch it again now that I bought the game once more from GOG. And it very well might have been, if it weren't for all the bugs it had in its initial release! In fact, if it weren't for them, I think it could have easily been the as much of a memorable FPS title in the public consciousness as Half Life!

http://www.crunchyroll.com/sin-the-movie/episode-1-sin-the-movie-452832