Roughly 22.5 hours , depending on how thoroughly you explore the ship's decks.
“GOG is the most customer-friendly, with better refund policy, meaningful ownership of games through DRM-free installers that you can back up.” Reddit · 4 months ago System Shock 2 Free Download (GOG)
The GOG version is highly compatible with the "SS2 Tool," which facilitates the installation of high-resolution texture packs and "Nightdive’s Enhanced Edition" features. Completion Time Roughly 22
You choose between three careers—Navy (combat), Marines (heavy weapons), or OSA (psychic powers)—allowing for vastly different playstyles. Roughly 22.5 hours