I know we all hate pre-orders, however pre-ordering this gets you a free copy of System Shock 2 enhanced edition when it's done. (Pre-orders only)
Additionally Nightdive Studios are doing great work, and you can play the beta/demo for free on Steam.
It's current;y $49.95 on Steam.
Update: Thanks to ozbs25 for point out Humble choice members with 20% can get it cheaper: https://www.humblebundle.com/store/system-shock
If you happen to have your full 20% off discount with Humble Choice it's cheaper there. $39.96