Hey, finished a 5 hour game on a one system map (was a very large system though), at the end I had about 800k credits, 250k metal, 150k crystal, everything researched etc..
Now here's the thing, getting near the end I had about 50 fleet supply left and then researched the "Returning Armada" in the vasari empire tree, I had plenty of phase gates scattered around in my systems and when they finished my fleet supply went down to -405! yes negative supply...
Don't know if this is intended or not but this might cause some major imbalances against TEC because they don't have anything similar to this last I checked (not to mention that phase gates are silly overpowered in the endgame) and this means you can always get a bigger fleet as vasari if there is a stalemate or something like that.
Also, culture definately needs a re-design, granted the computer doesn't really do much to counter it and against the AI this makes it insanely overpowered, HOWEVER i think taking over a planet is too much, my idea is that it could severly cripple it, for example severly decrease the income it provides because workers are on strike or whatever but not actually taking over the planet...
I'll return with more feedback but this is what i've noticed so far! Great game btw

edit: oh and another thing, this game really needs an easy way to select "military units" on selected planet, selected solar system and all military units. This especially since when you have the vasari returning armada you'll have units scattered about in all systems you have phase gates in and have to zoom around selecting those (even doing it through the empire view is anoying when you have 20 planets or so =P)