Has anyone seen Gantz?
 

It's a pretty old anime and has a live action movie as well. If you're interested watch the anime before the movie.

This anime was so distressing to me and is the first anime that I can say that I hated and loved at the same time.

Anyone else seen it? If so, thoughts?

I saw maybe four episodes, definitely need to find it again. It was pretty interesting, if I recall correctly.