One of the most unusual FPS games I've ever played. I'd even describe it as a puzzle game with an element of FPS
The FPS element of the game is rather simple, there are no more then 2 bad guys you can encounter at the same time. The game tries to make fight challenging by making handling of weapons somewhat realistic: they are slow to reload, no crosshair, aiming is difficult while moving as the barrel swings right and left. However, for anybody with a slight experience in FPS genre, this is no challenge at all.
There are puzzles to solve in order to advance. Most of them are old school: find a door, flip a hidden switch, protect a room, etc. The way you start puzzles is very unusual: you relive final minutes of the ship's crew dead bodies of which you occasionally stumble upon. The objective is of course to survive.
The game adds a little but nice touch to the storyline: a parallel story, bits of which you find here and there. It's a story about the ancient people and a guy named Danko who saved them. The story itself doesn't do anything for your cause, but finding bits of it keeps your interest up to learn more.
There are only 2 things I didn't like about the game: optimization and the final boss fight. Seems like the game wasn't optimized well enough, there were several moments when the framerate slowed down to a slideshow even on my gaming rig which runs all latest games with all settings maxed out. The final boss fight was just weird and out of place. Not going into much detail I can tell there are many much better ways to get in touch with the master of time.
The game is surprisingly good, I'm not sure why it didn't get more coverage. And like I said in the beginning, this is perhaps the most innovative way to mix FPS and puzzle genres I've ever come across.