I began the game on Terminal Moraine, the map with Two isolated bases.
The map is built for two on two, but I played on One on One for extra funsies.
Anyways, things went' well for about five minutes, I got two big bases, upgraded supply depots. Then I find the computer somehow amassed a huge army. In a last ditch effort, I sent out a spartan to get me a new base before the old ones were destroyed. I sent him around the enemy and over the lightbridge onto the left Isolated Base, where I found some rebels had moved in which sucked since even one spartan wasn't much to hinge your whole game on.
Luckily there were two build sites outside it, and I built a supply depot to keep my economy running, and a barracks, which overran the rebels just as my main bases began to fall completely.
There was a period of peace, while the AI either tried to look for me or was busying itself chasing its own units, or something. The AI isn't very bright about what it does when there's nothing to fight. I built my base up, took the little reactor, giving me just enough to build some cobras (anti-vehicles that can lockdown into artillery). The AI finally found me after I sent out marines to secure the other side of the light bridge, and the battles began.
Lo and behold, the AI had built a scarab, which is terrifying in the most lopsided way. For reference, the strongest unit the UNSC can build is a vulture, and it takes three to bring down a scarab with any faithfulness, and even then two usually die unless they have the upgraded barrage and it's used (natch). The scarab lumbered across the light bridge, my cobras, fully locked down, firing and doing what looked like no damage, though it was the same kind of damage that obliterates Wraiths in two shots. The scarab stopped on the light bridge, began firing it's laz0rs at my poor cobras, got one, switched to the other, and then had a meeting with gravity as the light bridge turned off.
I admit, I took a moment to laugh as the AI lost half a scarab to a really stupid mistake.
But my luck wouldn't hold. I had to build some vultures, and so I took down the barracks outside the base (I didn't need it anymore, I had on on the base itself), and built another reactor, pushing me to the ability to build Vultures.
In the meantime, I fortified my location, building turrets, taking towers with ODST, repositioning my cobras so that their range went just over the bridge where the AI was already congregating a huge army to attack with. And, a single hornet, a weak aircraft barely able to hold its own against grunts. But the suckers are fast, numerous, and can fly over obstacles, like the mountains surrounding the map. I sent him off behind the enemy bases, and flew him around to the other Isolated base, where I repeated my old strategy and built another hyper-fortified location.
By this point I had killed three scarabs. Three. That's an accomplishment on par with competeing in the olympics, going into space, or managing to get the damn toast to toast just right. But I had a plan, and the resources to replace my losses, and I had four vultures, which by this point were extraneous. I had upgraded my MAC Cannon fully, which let me take down scarabs without anything but a visual on them. It also freed up a powerful force, which swept across the map, destroying bases and then plopping down my own.
I didn't build in these new bases, they were only there to clog up the spot and let me know where the AI was. All I built were turrets, and those were distractions, as I intended my Vultures to come sweep the floor with any AI troops.
This proved the end to the AI, which broke their armies upon my fortified position (?) one last time, as the Vultures ate away at their resources. They could no longer afford the massive cost of the Scarab, then about halfway through I destroyed their temple, meaning they couldn't do anything but build grunts and weep.
I won a victory watching their last unit, a ghost, fire ineffectually against one of the bases I forgot to build turrets on. He was the only one left. A lonely, lonely elite.