Somethings wrong with the campgain. After misson 3 (the infamous Seige) and the torian misson after that, every misson I did was like it was on cakewalk, and not normal. It was a matter of researching plantary invasions. The AI didn't try and capture one planet, little lone build a single spacefleet.
Also, anyone got any idea which missons change if you win or lose them?