The Axolotl Project tells a very interesting and often gripping SF story. I especially liked the action scene and the descriptions of the aliens. There is also a final decision to be made, which, even though a bit foreseeable, draws the player right in. There are no real puzzles, and the amount of thinking required is just right as to not distract from the story but still keeping this interactive fiction as opposed to just fiction.
I have a few nibbles, though, which put this closer to a three star game then a five star game for me. For one, some technology seems rather old fashioned for a moon base. Sure, there are fully automatic cleaning robots, but also password authentication and (Spoiler - click to show)old fashioned secret doors. Also, some texts are rather long-winded, especially compared to the generally very dense and to the point writing in most parts of the game.
Still, all in all a satisfying SF game and a good example of what can be achieved with Twine.