The Mothership PSG is messy, wonderful, disorganized, intuitive, counterintuitive, etc. House rules are required to make the system work fluidly (use the excellent ones on Traaash), and the financial system in the game is broken. Ships repairs cost upwards of hundreds of thousands of credits, while ammo and gear is incredibly cheap. And yet, ships clearly are intended to be an important part of the system, given the large part of the book devoted to them.
As for enemy units? They aren't here - the most you'll find are some mercenary tables with thin descriptions on how to use them. Thin descriptions are the order of the day for much of Mothership - this is clearly a game in its first, early state.
That isn't to say that excuses it completely. We're not just beta testers - we're hoping to have fun in a scary, sci-fi setting. I'm happy to report that Mothership IS fun, but it's not for the timid. While your players battle the incredible stress and panic system (a true highlight), you'll be battling your own brand of stress: how do I make this game work? Take their skills system - a lot of it looks like usefulness will be based around warden discretion. Not true! If you scour the PSG, you'll find little mentions of HOW most skills get their usage. Why are these descriptions scattered aimlessly through the book? No clue.
Take as an example the skill of "Firearms." It doesn't say what it DOES. Then, a few pages later, with the weapons, a note! If a weapon has (Firearms +10) in its description, a PC with that skill may add their skill benefit when firing. Unfortunately, none of the weapons HAVE Firearms in their description...
I wouldn't recommend Mothership as a jumping point for a new warden, or even for a group looking for a new game to campaign in. As a system for one shots, though? Perfect. They've even developed a good one in Ypsilon 14, also sold here for quite cheap. I'd wait and see what comes next for Mothership for anything longer, though. This game has a galaxy of promise.
[4 of 5 Stars!]