Well....in the end my AI8.3 game turned out to resemble WWII Russian Front (a la HOI3) in an eerie way:
(1941) I started out briskly with operation Barbarossa: conquering planets with superior forces. This went all right until I lost a significant part of my fleet against a IV planet (Moscow) with forcefielded SF Command Posts, losing me a lot of time and giving the AI the chance to rebuild. This partial defeat was mainly caused by a sudden loss of mobility of my main striking force (Teleport Stations) in the Russian mud. For some mystical reason, the previously dominant Teleport Platforms never regained their supremacy on the battlefield (read: X patched them). Additionally, the enemy suddenly started deploying T34 EtherJets in large numbers, a weapon which was quite effective against my massed armor, but even more in a role as partisans behind my lines.
(1942) Once my fleet was rebuilt, my offensive resumed. Moscow and another few planets were taken, until I ran up against another IV planet: Stalingrad. A terrible battle of destruction occurred. More and more of my resources went into a big meatgrinder. I had the AI down to one forcefielded SFC post, when suddenly Operation Uranus was launched by the AI in the form of its first raid: a big III raid in my hinterland. The fleet had to abandon Stalingrad but did manage to defeat the raid rather comprehensively, capturing scores of the precious III cruisers. In the mean time, partisan raids were increasing, tying down precious ships and draining resources needed desperately at the front.
(1943) The fleet returned to Stalingrad and took it, then launched itself to the other IV planet in the strategic perimeter (Kursk). Another epic siege occurred where the Haagenti forces ground forward delaing and taking terrible losses. This too was too slow, as another raid was launched. The fleet had to retreat, never to return to Kursk again. The raid was level IV and the battle led to significant casualties. Partisans were now regularly destroying several tractor turrets, other turrets and garrison cruisers. Resources and especially cruisers were in shorter and shorter supply.
(1944) Before all these could be rebuilt, another IV raid was launched. This turned out to be the destruction of Army Group Center. The raid was beaten off, but it was clear that the war was lost, as the fleet had lost a significant part of its irreplaceable elite troops (I once had about 250 IV cruisers, all parasited). Partisan raids, supported by hordes of the dreaded T34-EtherJet, rose to a level where they would now occasionally overwhelm a garrison and actually conquer a system. Reconquest took time, attention and even more valuable resources.
(1945) The end came mercifully swift. The fleet had rebuilt itself, albeit to a weaker level than before. A 2nd III raid hammered into its veteran cadres, but the raid was beaten off. albeit with heavy casualties. Shortly after the last hammerblow fell: "A raid is forming at level IV planet". All remaining forces were gathered for a desperate last stand, all available resources were poured into vast hordes of turrets under forcefields, supported by endless minefields. Every available man was mobilised, every remaining weapon was deployed, including the strategic reserve of carefully hoarded parasited IV fighters, autocannons and Etherjets. All in vain, they were less than a speedbump against a ravening horde of more than 1000 IV ships.
Twenty minutes later the triumphant enemy entered Berlin, and scant minutes later the HaagentiBunker was successfully stormed, sweeping aside the paltry garrison. Peace reigned again in the universe.