Not many people are subscribed to the 5X forum. You would get more answers on the main Steam discussion forum for the game including from 5X players. I'll give my opinion though.

I made this mod and have played the game since release, and I find Extreme difficulty to be quite hard. I have never beaten the game on Impossible, and I don't know how others do it. I usually find it comfortable but a bit easy to play on Very hard.

As for general strategy, unless you are playing lithovore the most important deciding factor in who wins the game is population. On extreme, the AIs will shoot past you in population early on and there's nothing you can do about that. But the goal is to stave off war long enough to catch up to them. The only way to catch up is to have more eventual population capacity than them, which means more planets.

With that in mind, I try to stake out important choke points, get military outposts early, and seal off as large a territory as I can as quickly as I can. Engaging in early diplomacy with the AIs will help stave off war, but you have to maintain a sufficient military force or it's inevitable. You need just enough forces to form a deterrent while you backfill all the planets you claimed in your territory, which means you need to build a flood of colony ships and take every planet and prioritize techs like microbiotics and terraforming. Have a completely sealed off territory and don't ever allow open borders until you have colonized every single planet.

You also have to take advantage of the game's growth mechanics and keep all planets at half their max population for optimal growth, which means sending civil transports with every colony ship and waiting to build colony ships until your population is at or above half. There's some Steam guides in the guides section that go into more detail about this.

Eventually you will have a greater production capacity than the AI can manage in their smaller territory, and you can pump out all the ships your command points can allow and take them to war, starting with the weakest opponent you can get to.

Along the way, you might need to take some risks, like shooting down enemy colony ships even though it's a steep diplomatic penalty, or doing early invasions of critical choke-point planets that the AI manages to grab first but hasn't yet built defenses on.

Research is secondary, but still important. Planets without much to offer for production or food capacity are ideal for having a lot of researchers. When I get a huge poor terran, I build the needed infrastructure then throw it on autobuild with the full population on science. You can also get a lot of RP early on through treaties and asteroid labs.

Hi Spud,

Thank you for your thoughts! I suppose it's comforting to know that I'm not the only one who struggles with extreme.

I'd say I'm doing most of what you're talking about here already actually. We actually play very similarly, I usually start out spending the first 100-200 turns on claiming territory much like you describe. On huge galaxies though, I've noticed that even if I'm successful at carving out the largest territory through military outposts and war deterring fleets, it takes so long to fully colonize it that I can't outscale fast enough unless I turn off the science win. I start getting notifications from the humans or from the psilons building their science win buildings when I am finishing up with colony ships.

Maybe I just need to turn off that win. I'm not losing in the military or territory sense, generally.

Disclaimer: I play without the science victory and have modded the game a bit, but it shouldn't change the main point that I want to make.

I never saw in the description of play styles mentioned how to use the civil transport.

There are planets that can very easily produce lots of food for new colonists and there are planets that don't have a good biome to do so. So, I always go for the good biomes first and immediately after settling a planet land a few civil transports to ramp up production or food output to make the planet useful. A planet with a colony ship and a civil transport is twice as efficient than one without the extra civil transport, with two civil transports it is three times as efficient. It even grows faster being closer to half population.

The planets that don't have a good biome should never grow their own population. They should be completely filled by civil transports from the efficient growth planets. As they are completely filled with population, they can quickly develop and also start creating some science from population. It is better to fill these up with population compared to having a lot of single population planets that are barely developing.

The growth planets do nothing else than colony ships and civil transports (mostly the latter). And since indeed growing population is a lot more expensive when close to the population cap, you do want to keep them a bit below the cap. But it can be a bit over half the population as the cost doesn't go up that dramatically and you do have more population to produce food, production and income then.

I usually (with some population growth bonus trait) can keep up with population, even lead.

But I agree that it can be hard (on Extreme) to keep up with technology with for instance a nicely isolated Psilon empire that doesn't have to defend itself early game and can just develop non stop.

I'll admit, usually my approach for colonists and colony ships on planets is that I send 2 civil transports with every colony ship, so every colony starts with 3, and then grows from there. I had heard that the growth formula is mostly maximized at between +3 over the minimum and -3 over the maximum population.

I'm generally finding myself at about 3rdish place out of 9 empires in population around turn 200 doing it this way, with my territory still not fully colonized so still room to grow, but maybe i could squeeze out more population faster by really micromanaging planets to stay around half cap.. sounds kind of painstaking though.

You don't want every planet to create their own population. Population is expensive to produce if you look at the amount of food needed, so you want to do it on planets that are excellent at producing food. You want to minimise the amount of workers on some backwater planet trying to create another population by working some 1 or 2 food tiles. That is not an efficient use of your workforce.

Create them on some planet that produces loads of food per worker (Gaia, terran, ocean, maybe swamp preferably with a food or growth special and all the food and growth buildings) and ship them over until the maximum that you can maintain on the poor food planet.

The poor food planet can focus most of them on production and science until it is developed completely and then it can do science or maybe build a ship the planet is rich

It is all about getting the highest production, food and science out of your workers.

There is a small cost to a civil transport, but it is fairly low compared to the food cost of a population. So as long as the difference in food production between the good food planet and the poor food planet is big enough, it is better to create the population on the good food planet and ship it over.