I read over most of the rules and have a few comments...
1. Zangid does not roll off the tongue very well. Is it like "dang"?
2. Taurans and Terrans are too similar in "words" and could be misheard at a table. Maybe simply Humans? Earthens?
3. Time Travel stuff is great!
4. Space combat is simple...in a good way.
5. Charts for artifacts later?
6. “Running the Galaxy” so needed to be written in this book.
#6 is not sarcasm, but just a reflection on how many game masters suffer from analysis paralysis when dealing with a canned world. The book is looking good as it has the MF/LL organization and feel to it. The promotion system introduces a simple "skill system" to the game and can easily be used with a MF game. I think an example game session would be good, similar to LL...for people new to the Star Ship genre. There is not much more to say since much of it is similar to the solid games of LL/MF. I can already see an LL version of Spelljammer coming from this somehow. This would also be good for having MF adventures where mutants find space ships and continue adventures into space. I am not much of a critic as I am a fan of the books and layouts already so you basically had me at "LL/MF Compatible". This is all exciting stuff.