I have been playing a Rebellion game for about 10 hours total and I have found the AI is good, really good.
Map (I am the red empire)
Picture of right chokepoint (with my fleet) (the top left one looks mostly the same)
Size of my fleet
I was on a random medium map where I had a ton of metal, but hardly any crystal to speak of. I was a TEC Loyalist, so I conquered a few planets at choke points and had about 7 planets total. I sat in my corner, not even really doing any diplomacy, storing up the resources to build starbases and novalith cannons and a titan. I researched all of the upgrades for defenses that would be helpful (militia armor, militia guns, 2 starbases in a gravity well, etc) and was holding them off pretty good.. until they sent a level 8 Advent titan at me. It was the one that can convert your units to theirs and they had a pretty good fleet with them. If it weren't for my mines and a huge fleet, two starbases, and a level 3 Titan, I'd be dead for sure.
Since I hadn't really sent out any scouts after the beginning of the game, I had no idea who was left. It turned out that two advent factions (both the blue ones) had allied themselves and were hell bent on my destruction, probably because I was the only one left. With that they would send a fleet to one of my choke points and I'd have to send my titan (which eventually got up to a level 8 with the 1250 xp point enemy titan kills) and a very large fleet to hold them off. As soon as I was done with that fleet, then the other faction would send their fleet with a level 4 titan to my other choke point, which was not as much of a problem but still there.
After both enemy fleets were (sometimes) narrowly defeated, I could try and branch out to some other systems (such as ice ones that I really needed). The problem there was I needed to rebuild and expand my fleet which took money. I also needed a lot of money to build more starbases to defend those planets I just got. In other words, the enemies were a real pain. I just plain don't know how to defeat them other than to give up most of the planets I have and try and take out their titan building facilities. If I loose too many planets, I will have no outer defenses and I will loose a lot of income.
Does anyone have any tips?
An alliance would have helped, yes, but it's too late for that.
I was playing against these two enemies that were both at the unfair level, so maybe that was the problem, but they were really hard. (Again, perhaps too hard, devs)
I really love the Ankylon Titan and it's "ultimate" ability. Lowering the enemy fire rate by 50% and yours up by the same at the first level is really helpful. The devs might want to adjust the auto AI use of it as it only lasts 30 sec I think and the Titan sets the ability off as soon as it enters the gravity well, so neither it nor the fleet I have can usually attack the enemy with the bonus.
The Corsev "ultimate" is also really good, especially when used on a level 10 Kol with fully upgraded rail gun and the antimatter consumption reduction by the Dunov. Super deadly trio there.
Also with the mines being unable to be revealed, I was getting hit hard when attacking planets.
I really can't wait for the Vasari. Will we have to wait till the final release to play as them?