My first Human target would be their most exposed planet at the edge of their territory, the small colony of Morrig. It was only lightly defended, so it would be a nice tuneup for my future efforts against them. Here was the situation as my fleet was about to arrive:
Yes, I already have population transports incoming; I was quite confident I could take the planet. And with only 4 bases, it was indeed no contest; the Human ships in orbit fled from my stack of large Graviton ships while a swarm of bombers easily trashed the planetary defenses. I had to pause for a few turns after taking Morrig, with half of my ships defending Lyae and the other half defending my new aquisition, but Lyae was soon able to stand up some bases to protect itself.
That allowed me to move on to Reticuli to the north, the planet I was most interested in taking. Reticuli was a Jungle world with a base size of 110, and the Humans had already terraformed it with +40 tech into a max size of 150. Since I had Improved Robotics IV with the Meklar, I could build 6 factories for each population point there, adding up to a grand total of 900 (!) factories. Wow. Can you see why that was such a hot commodity?
Of course, that meant that the Humans had well over a hundred defenders of their own there, and so taking the world intact would be no mean feat. I had Spica send almost a quarter of its population turn after turn, regrowing them with max ecology spending, providing a steady stream of marines to wear down the Human defenses. You can see that in action below:
The process is about halfway complete here, with more marines still on the way. It didn't help that I was even in gropo tech with the Humans and couldn't kill them at a better than 1:1 ration. (I traded something obsolete to someone for Hand Lasers at this point, since I lacked any kind of ground weapon. Better even a little help there than none at all!) Eventually, my population swarm ground the Humans defenders into dust, and I took the planet:
Picked up a couple of techs in the invasion, but nothing too terribly significant. More important was the 334 factories, which allowed me to flip the colony into a massive Meklar base in a matter of turns. With the help of more population incoming from Spica, Reticuli was quickly able to achieve a "decent" rate of factory construction:
82 factories per turn, heh. Already over 500 production, and that will keep going up until it nearly reaches 1000. Once I killed the incoming Human ships, I would be able to move my own fleet forward to Nordia and continue the attack.
I tried to make nice with the races other than the Humans, but my growing size and power slowly dropped relations into the toilet with pretty much everyone. First to go were the Sakkra, who flipped sides and took up the Human cause sometime around this point. Their fleet was not powerful enough to crack my core worlds, so mostly this just gave me another spying target. Sadly, the Klackons also flipped out and declared war on me. I would have preferred to stay friendly with them, but it was not to be.
Well, if that's the case, only one thing to do:
I couldn't let a Terran 100 planet go to waste, could I? This loss decimated the Klackons further, although for the moment I was more concerned with standing up Kholdan than hunting them down in their final remaining colony.
When I wrestled Nordia away from the Humans (still doing this the hard way, with invasions at each world), I picked up this major tech:
Bingo! I'll happily add another 20 million people (and 120 factories) on all of my planets, thank you. These terraforming steals from the Humans were of especially high value, because my Planetology tree was lacking in many of those techs. That's one of the coolest parts of this game, which simply doesn't exist in Civilization at all.
Here's where the galaxy stood after the inconclusive 2475 vote:
I've taken half of the Human empire for my own in the north, and their home planet is the next target on the list. Of course, the Humans are still duking it out with the Silicoids and Mrrshans in the west, as you can see by that one green flag. Silly AI. You can also see that I've taken Kholdan away from the pathetic Klackons; I could have wiped them out prior to this point, but I decided to wait until after the 2475 election to avoid the reputation hit until it was too late too matter. Devious, huh?
The green ships at the north of the map above were incoming to Nordia, where I used some reserve spending to accelerate factory and base construction. In addition to my fleet, I would also managed to build 10 bases by the time the Human ships arrived. The apes had mostly been running from me, but here they had finally managed to concentrate their ships into a decent-sized stack. This could be a decisive battle!
The most immediate danger was the 4-pack of large ships at the bottom of the screen, since that design was packing death spores. I targeted them first with the missile bases and killed them before they could close with the planet. Next up was the 5-pack design at the top of the screen, called the Escort ship. It had a Repulsor beam onboard, which I found to dismay made it impervious to my 1-range gunship design! (First time I had seen that particular special in action.) Fortunately, my bases were able to kill them all off without problems. The other ship models were worthless junk not worth mentioning. I killed off the whole fleet at the cost of 4 of my large ships:
That pretty much did in the Humans as far as fleet strength was concerned; they had some more ships moving around, but nothing in terms of a SoD. Now it just remained to establish orbital supremacy and muster the population to invade each world.
Looks like that won't be a problem here! 
(I sent a lot of population to overwhelm Sol and stand it up quickly. A LOT.)
I invaded and wiped out the last Klackon colony too, down at Proteus in the center of the map. Sorry guys, but you shouldn't have declared war on me.
Yep, more good news. Unfortunately for the Humans, I had picked up some improved Force Field tech since our earlier battles, and my machines were now sporting spiffy new Armored Exoskeletons. That turned what had been even battles into a rout for my side.
By 2500, the galaxy map was beginning to tilt decisively in my favor:
I've completely broken out of my corner now, and the Meklar have been totally unleashed upon the rest of the galaxy. Once I finish ploughing through the remnants of humanity, the Sakkra will be next in line for elimination. One race at a time, however - at least for now.
Everyone else was less than pleased with me by now, but I no longer cared. I had way more than enough votes to block any council votes, and I used my Always War situation to turn loose my spies on everyone. With vastly superior Computer tech by now, I was able to pick the AI tech trees clean in short order, grabbing everything of value.
Let me show you my own tech tree at this point:
I'm waiting on several major tech breakthroughs here before designing a new round of ships. Probably the most important is the one highlighted, making the Propulsion leap to warp 6 speed. I've been using warp 3 even since pulling it from that Artifacts world! The increased speed will benefit my transports the most, of course (leaping from warp 2 to warp 5) and it will come in handy on new ships as well. The other three techs are also very important; Computers will give me Improved Robotics V for another round of factory construction, and Planetology is about to pop Advanced Soil Enrichment (Gaias, yay!) Those two combined will make for a sickening amount of factories. Finally, I'm about to get my hands on a Planetary Shield (Class X) at last, having lacked access to Class V for most of the game (although I did eventually steal it). That would allow my ships to move forward with complete impunity, knowing my own worlds were impervious to attack.
When the techs come in, I spend about a dozen turns terraforming and adding factories/population. That led to scenes like this:
1470 factories! Why yes, I DO believe that I like the Meklar! 
My major shipbuilding planets also used this time to build Stargates, another tech I had lifted from someone else (in this case, the Sakkra; wasn't in my tree). That would come in handy for the upcoming purge... In the shot below, you can both see the destination for my stargates at Kholdan and view the imminent demise of the Humans:
That was all she wrote for the Humans; they had been fine foes in this game, but ultimately my production edge was simply too overwhelming for them to combat.
I built some Huge ships once I had warp 6 engines to use as escorts, but since I still lacked for good gun technology, they weren't really all that great. (I was still employing those Graviton beams from earlier!) I did slap some Antimatter bombs on them, but the Huges were intended mostly to protect my real weapon, this Pulson missile boat:
With Ion Drives and the Inertial Stabilizer (another tech theft prize), I could reach a combat speed of 5, able to move twice and shoot before the enemy could even react. I never knew what that meant before playing this game, when reading other reports, but now that I do... let's just say it's a good thing. Swarms and swarms of these missile boats were ordered into production across my empire, and routed through stargates to the Kholdan front.
By the 2525 election, I had enough population dominance to vote myself the winner, for a Conquest victory. However, I contined to abstain, determined to play this one out to the bitter end. This galaxy is too small to share with anyone else. We are the Meklar, and all must be assimilated!
The map situation from the same year:
Up to this point, I had captured everything intact with population invasions rather than using orbital bombardment. That was partly due to my desire to stand up the colonies faster, partly so I could loot tech from the worlds, partly because I am by nature a meticulous and careful player who likes to leave no area undefended. However, from this point forward I would only capture a few worlds (for range considerations) and burn down all the rest. I had an unbeatable fleet of highly advanced ships, and it was time to end this game pronto.
Before getting into that though, let me show you the galactic mineral situation:
Six different Rich or Ultra Rich planets (there was another one in the extreme west I hadn't scanned yet at this point) in this galaxy, and NOT ONE of them was on my side of the map! Unbelievable. 
The Artifacts planet did help me significantly, I'll readily admit, but you'd think at least one of those hostile planets near my start would have been Rich. Oh well. I'm a little surprised the Silicoids didn't do a little better with all those Rich worlds to pick from, but the Mrrshans basically dragged the rocks down with them in this game. Silly cats.
I took Sssla as much for symbolic purposes as for any other reason. My gropo tech was so much better than theirs, I was killing the lizards at about an 8:1 ratio. It was rather sad, to be honest.
This, however, was a much more typical result of my combat:
Fleet shows up, kills any bases that might be present, planet gets glassed out of existance. Rinse and repeat as needed.
Five or six turns later, the galaxy map has already changed markedly:
No more Sakkra. On the plus side, Meklar cyborgs everywhere are enjoying their new lizardskin handbags throughout the holiday season. 
At Cryslon, the Silicoids find out that my Pulson stack can get off two volleys before they even get to fire back. Then while my stack outruns their slow missiles, my Huge stack drops its Antimatter bombs and finishes the job. This planet was noteworthy solely because the Pulson stack didn't take out the missile bases with one shot. (And considering how old this game is, I think the artwork for that Huge ship looks really cool. Anyone else agree?)
By 2537, there's not much left to write home about. My fleets will hit both of the remaining planets on the next turn. Extermination is assured.
The stats don't lie.
My first Extermination victory in Master of Orion, and it was a lot of fun with surprisingly little tedium. Much less than in a Civilization Conquest win, thanks to being able to bomb the crap out of planets from orbit. (The last ten turns probably took less than 15 minutes to play out.) I have to say, I definitely like the Meklar as a race too. Their slow-developing nature works well with my defensive, buildup-a-massive-hammer playstyle. And that artwork is just slick too. The Meklar leader looks so EVIL there! Ruthless Industrialists indeed. I'll definitely try to come back to them again at some point. 
Getting out of the corner at the start helped make this game feel unique; I enjoyed adapting to the unusual circumstances, and I hope it made for an entertaining story too. I'm sure it could have been done faster, but there's no clock or scoring in MOO, and I was having fun. I think that's what matters in the end.
