Oxygen is a compact puzzle game set in a space station that is, even galactically speaking, in the middle of nowhere. The intro talks about the Galactic Empire, which made me think first of Asimov and then of Star Wars -- so it was a relief to find that this was not a piece of fanfic featuring Hari Seldon or Jabba the Hutt. (That Spaceballs joke about Pizza the Hutt was just too easy, wasn't it?)
Rather, Oxygen puts you into a situation where, as the on-duty technician of the space station, you must regulate the airflow from the leaking central oxygen tank to two smaller oxygen tanks. Doing this isn't terribly difficult, because the console has only four possible states, and you are provided with a useful chart detailing the effects of these states. But things are spiced up by the fact that the two oxygen tanks are attached to different parts of the space station, one of which is taken over by striking miners; and those miners also control part of the air flow regulation system, so you'll need to work with or against them in order to achieve certain results.
Some reviewers have said that the game implements the Prisoner's Dilemma, but this is in fact not the case. The Prisoner's Dilemma is defined by its pay-off matrix where (a) if we both help each other, that's good for us both; (b) if I help you and you rip me off, that's even better for you, and exceedingly bad for me; (c) if you help me and I rip you off, vice versa; and (d) if we both rip each other off, that's bad for us both, but not exceedingly bad. The interesting thing about this situation is that we need to cooperate in order to achieve maximum success; but at the same time, it is always better to rip the other guy off. This leads to some tough paradoxes, which you could fruitfully explore in a game.
Oxygen doesn't explore those issues, because it's pay-off matrix is completely different. In fact, the player can force the other side to adopt the strategy that is optimal for the player's side. So although the interaction with the people at the other console does add something to the game, it is not, in the end, the main puzzle. The main puzzle is finding out what the optimal ending is, narratively speaking, and then achieving that ending. I managed to get to the optimal ending, where the miners and the captain sign a contract and you stay alive and Andre gives you free drinks -- but it wasn't easy. It was fun, though.
Yes, Oxygen is fun. It is wildly implausible: what engineer would think up an oxygen control system where you have to manipulate two consoles hidden in different obscure and almost unreachable parts of the ship, and where it is impossible to save more than 75% of the oxygen, but possible to lose it all? But it's fun. The central puzzle works, and the story surrounding it is good enough to sustain interest for the time it takes to work through the puzzle.
Although no testers are credited, the game is very polished. I do feel, though, that "attack/cut cable with screwdriver" should have been recognised -- I had to resort to the walkthrough to get past that guess-the-verb puzzle. Also, perhaps the chart could fall out of the book a little earlier, because I had at first given up on reading through it all.
But those are small complaints. This game accomplished what it attempted to achieve.