Some semi-organised thoughts after playing it a bit in the past two days. I haven't finished a game yet, mind you, so these are really just early impressions.
- Obviously based on MoO 1 and 2, duh.
- 7 playable races. They're generally similar, each having two extra abilities like pops producing more of some resource or having a unique early game tech. Humans seem to be Hard Mode, since their two abilities are that A) they have NO HOME PLANET and start with their population onboard transport ships, and B) they start with two Colonisers rather than one. No custom race option. There are also some dozen minor races, more on these later.
- The game seems to aim for a spot between the first to MoO games on the abstraction vs. specific options scale, closer to the second one, though I suspect that more familiarity with combat, ship design and economy might reveal extra depth.
- Every planet has a pop limit and a number of development slots based on the above. Every pop unit creates production AND food AND research AND money all the time (unlike MoO2), but that alone won't be enough - and this is where development slots come in. Rather than building structures with specific properties like in MoO2, you have 5 generic buildings: Farms, Markets, Labs, Factories and Mines (for metal, you'll need a LOT for ships and space stations). Each building gives you a fixed number of resources per turn, and a bonus if you have a high enough population to fully staff it. Researching certain tech will automatically replace all buildings of a certain type in your empire with an improved one (3 or 4 levels of improvement). A single pop unit counts towards the staffing level of all different types of structures, which motivates you to avoid overspecialisation: a population of X can fully staff one Farm AND one Market AND one Lab etc., but can't fully staff two Farms or two Markets.
At the same time, some planets have resources that give you a bonus to all mine production, research etc.; in these places, some specialisation is a good idea. Also, ongoing tasks like Research sometimes give a set fractional bonus (Research doubles the planet's research, Mining increases metal yield by 1/3rd regardless of other values), while at others factors in other things (Produce Food gets you a bonus based on your Production points provided by factories). Therefore, you have to figure out the right ratio between generalisation and specialisation.
- An interesting addition is the idea of planetary zones. Every planet has 1-4 biomes on it, and different races have different preferences. Here's an example: a planet has the Vent, Ocean, Reefs and Forest biomes. You're playing the Giant Isopod Scientist guys, who are the best at populating geothermal vents, decent in oceans and crap everywhere else. If you colonise the planet, you'll have a specific population cap there. However, Humans are best in forests, so if you have some in your empire, you should transport them to your new planet: they'll start populating the forest zone that your isopods can't utilise, thus increasing the pop cap. Get a third race, one that does better on reefs or in oceans than either the isopods or humans, and you pop cap increases further. Since higher pop means more pop-based resource production, more development slots AND fully staffed bonuses for more developments, this is something you should do whenever you can. A multiethnic empire will also let you colonise planets that your main species couldn't, at least not until some relatively late-game tech.
- Minor races can be acquired by settling their home planets (or conquering it from a previous owner). They help you fill out your biome versatility described above, and they often also have interesting quirks. One species is a crappy producer and breeds slowly, but doesn't need food and can live on airless planets. Another one is unique in having the best affinity for the Metro(politan) biome and is unaffected by morale factors. A third one provides some science production but are otherwise useless troublemaking cunts, but they're the native inhabitants of the super-productive Gaia planet and you'll have to put up with them if you want that place. And you can't ship them off to a shithole because they refuse to migrate.
- Transports and trade are elegant. There's a transport ship type that you can produce and then manually use to ferry around population units and ground assault troops. You can also tell them to go into the off-map trade fleet pool. Once there, they will automatically appear to carry out your population transport orders then go back into the trade fleet. The fleet automatically ships food from place of surplus to places with a deficit, and ships not used thus automatically generate trade revenue as long you have enough trade lanes between your planets (or leading to other empires with a trade agreement). As a point of criticism, the limited number of trade lanes seems to become a purely theoretical issue beyond the early game, since you'll ALWAYS have more of them than you can hope to build transports for.
- Research is pretty straightforward. There are several branches (energy weapons, projectile weapons, missiles, social, physics, etc). It's pretty much what you expect. Late game tech seems to give you stuff like Doomsta... Mobile Planetoids, terraforming, planet construction, etc.
- Ship design & combat. Combat is pretty much like MoO 2 with a lot of rock-paper-scissors considerations. Lasers are accurate, can get the Armour Piercing and Rapid Fire mods, but need to batter down shields first and use up lots of energy from your ship's generators. Projectiles are less accurate but can get the Long Range mod and penetrate lower tech shields. True to MoO, missiles are shit because they take time to travel to the target, get shot down by Point Defense and your run out of ammo. You also have MoO staples like enveloping weapons that damage shields on all sides of the target or kill enemy marines if they penetrate armour. You also have boarding action and small craft (fighters and bombers). Ship design works by dragging your various types of weapons and other gear into hull-dependent slots and then swearing when your generator doesn't have enough energy for all your systems. Bigger doesn't always seem to be better; you CAN waste one of your Dreadnought's weapon slots on point defense, but you might be better off puting a heavy hitter there and building a smaller Escort Cruiser specficially to act as screen for enemy torpedoes and small craft. You also get to design your starbases and planetary defenses. One really useful addition would be the ability to set up your fleet before a battle, so they each start where you want them; right now, I have a fleet of two Dreadnoughts and three Heavy Cruisers, and one of the cruisers (the one with the shortest range weapons) always starts behind the Dreads and by the time it maneuvers to the front the battle is usually over.
- Some quality-of-life improvements would be welcome, most importantly a way to spread orders over several planets. You might have dozens of systems in the late game, each with 2-3 inhabited planets, with a good half of them set on automatic research or mining. If you research a tech that gives you an extra development spot on all your colonies, you'll have to manually click through to all automated planets, tell them to build something in that spot, then send them back to research/mining, which is a chore; though I guess MoO2 wasn't entirely free of this sort of repetitiveness, either.
- All in all, I like it so far. Feels like MoO, and has that "one more turn" feel. Empire management seems to bog down once you grow past a certain size, but I also felt that with MoO 2 as well.