It's cool. The most mindblowing thing about it though, was how ahead of its time it was. Everyone was so busy playing games like Quake and stuff, nice as they are... and then out of nowhere these System Shock games came along which were so advanced, even most games today don't do half of it. They had a variety of grenades, frag, emp, proximity mines, and a whole bunch of weapons and you had to quickly switch between armor piercing bullets or anti-personel, there is hacking and research puzzles to solve and lots of different roles you can play, you can technically replay it three times with almost a completely different 'class' kind of like an RPG. And each of those can be built in different ways too. It's creepy as hell, and got a really good story, great level design, etc. Kind of like the Baldur's Gate of the FPS world.
Pretty much a life-affirming game for me :P Definitely in my top 5 of all time.