I just tried to review the replay of my first Beta 2 game, and I noticed that it was all out of whack.  Everything went the way I remember up until the point that I built my second and third starbases.  Those bases never constructed -- the constructors acted as if I had never issued the build order (one went to the build location and never moved again; the other kept following the ship that it was rallied to).

All the obvious differences I saw followed from those: a capital ship that was killed by my starbases never died, so it was able to rejoin the main AI fleet and defend the homeworld against me; the fleet that previously won the game for me was a few ships short (because that capital ship had killed them when I commanded them to head straight home after it died (that is, after it died in the original game)), and that capital ship was available for the defenders, so the last battle was nearly even, and I probably would have had to build a few more ships to finish the game off.  On the other hand, I had way more resources than I did in the original game.

I'm guessing there's just something a little funny about how starbase construction is saved / replayed at the moment.