I haven't played AIW2 for a long time. Last time I played, fleets were still upgraded by experience (I am curious why the current fleets are upgraded using Science). I had some trouble at the beginning because the AI was heavily using Zombification, though that became less of a problem once I slowly drained the AI's Warden fleet.
Near end game, I summoned the Human Resistance Fighters. They are really strong, but they don't always come to the right battlefield... Sometimes they warp into planets alerted by my forces just passing through.
Well, I won after about 10h, and proceeded to capture every planet, then went on a 100 second Super Terminal madness. I could have done longer by getting everything from the galaxy, but my computer was lagging at 25%.
=== Unit Reviews ===
The Cloaked Transport was awesome. I used it extensively, despite only having about 50 strength all the way to endgame. This was my workhorse fleet.
The Agile Transport was awesome in a different way. I used it extensively for defensive purpose, using Zombification units, melee units, and "factory artillery" like Railpods. I could reinforce half of the galaxy with just that one transport.
The Ark with knockback and door kicking fleet was also good. Combined with the Cloaked Transport and any factory, I could launch some good deep strikes in a 1-2-3 configuration (one fleet attacks, factory on adjacent planet, guarded by another fleet).
The Backdoor Combat Factory was awesome. I spent hacking points to transform one of my factory into this, and it was so much more survivable. Its Tackle Drones were also helpful.
Metabolic units including metabolic fleet and the Hive Golem are very useful, as salvage does not exist in AIW2. These effectively cut down half of my metal usage during the final assault.
The "classic triangle" of V-Wing, Bomber, Pike Corvette are quite niche here. I couldn't really find any use of them except to FRD on my defenses. I rather like ships that can act as force multipliers.
Also, I found the Cursed Golem to be disappointing, but that was probably because I didn't upgrade it. It got killed extremely easily, and cost me millions of metal to repair. Throughout the homeworld assault, this golem was at least half of the time crippled.
Compared to my previous experience, the AI Overlord Phase 2 is much more approachable. Although I had to read through a huge tooltip just to understand why I couldn't target it on the AI homeworld.
Instigator base seems to be... different? The AI often spawned them when I was performing deep strikes, and no longer put them deep into AI territory. Good news for me!
=== What I wished I have ===
Number 1: the ability to select only the fleet ships of a fleet. I just couldn't find a way to easily select all ships, excluding the flagship itself. Setting flagship to stationary doesn't work either, because doing so causes all new ships to follow previous orders. I usually want this to pop disposable units into a wormhole without risking my flagship, but selecting them was so much trouble. The only way I found was to move the flagship aside and box select, but I might be missing something.
Number 2: better documentation of all those unit types. The wiki is incomplete, and in-game tooltips are so dense (that said, an in-game encyclopedia would be awesome). While the icons are super helpful, at the end I just throw blobs of fleet into the battles with strength at least 2:1 because it was too much work to check on each unit. All I remember is: if there is OMD or Ion Cannon, kill it first; if there are Neucleophillic or Sabot, kill it first; if there is anything that looks like a Parasite, KILL IT FIRST.
Personally I find the AIWC's hull system is easier to remember than AIW2's number system, because the science tree does refer to hull types. I am no going to remember Armor > 90mm or Albedo < 0.3 but I will remember Polycrystal and Ultra Light. That is just me, and you don't have to agree.
Number 3: salvage. I really miss it from AIWC, because there are quite a few times I used up all metal reconstructing a planet's defense and fleets after fighting threat on one of my planets. I had to wait for some ten minutes just to get my fleet going. This was most apparent during a Fallen Spire campaign, though I was not doing FS in this game.