The Dead Cyborg Website offers the first episode in this "first person view, hard-sci-fi adventure game." This can be had for free, as it is provided on a "pay if you like" basis. Here's a trailer, and here's word:

“Dead Cyborg” is a free, donation based sci-fi adventure game for Windows, Linux and Mac. The story is about the meaning of life... and death... in a rusty post-apocalyptic metal and concrete world. Check the homepage for more information.

If you are keen on exploring the levels of fps games, you like the old text adventures, or the sci-fi classics (like Lem, Dick, Bradbury etc.) - you will like this game.

The game will be published by episodes (2-3 hours of play per episode). The first episode is now available on the homepage. The next episodes will come when enough donation is paid for the first episode. The full game will have 3 episodes (this is sure, not an endless story or something like that).