Utopian++++ is currently the hardest difficulty in the game, and it's quite the beast! At this level, expectation costs have risen considerably and come even faster than ever. To survive, you need a combination of skill and luck. Having won a number of times (and lost far more), I'm seeing a number of common strategies play out. This guide will hopefully help you win at the max difficulty levels, or at the very least, get better at the game!

UPDATE:
The ocean expansion has added all sorts of new projects, leaders, and more, as well as tweaked the difficulty levels a bit. After beating all the scenarios at max difficulty, I'm happy to report that all the advice I've given is still very much relevant. I have updated a few sections here and there though.

Let me know in the comments if there are other changes you'd like to see me make!

Regardless of what scenario you're playing, at max difficulty, you need to treat terraforming as the primary goal of your game. This is not surprising given the game is called "Terraformers". Why is terraforming so important? Hitting each milestone gets you one-time boosts of support, which are so critical in surviving mid-game. Additionally, plants and animals generate prestige and additional support, which are pretty much the only way to survive the mid/late-game expectation bumps.

What does this mean in practice? The sooner you can put down bacteria and plant spreaders, the better. Heat is important because most plants have temperature requirements, so focusing on Methanogenium (+1 heat) early on is recommended. Also, one spreader is not enough. I find that two to three is a good sweet spot. More is good, but only if you've got the resources and the space to do so.

Raising the ocean level is also important, especially since rainfall is needed for most plants. Prior to the ocean update, I always did that through space projects. However, the latest update provides several reliable ways to achieve water production, so I find that converting aquifers to ocean levels can be very useful.

Increasing atmosphere is good for increasing global support, since it increase radiation shielding for city populations. However, I typically focus on that after heat and ocean levels. It helps that there are space projects and leader powers (CO2 Imports) that can supplement whatever atmosphere your bacteria are producing.

Given that terraforming is so important, how do you get there? Here's what I think you need to prioritize during your game:

1. Production
The spreader buildings and space projects needed for terraforming are not cheap. You absolutely need a lot of production to win at this level. Titanium and energy are especially crucial because they're needed to build mines and robots. Also, while you do start the game with a lot of energy, you'll burn through it quickly via exploring and building. Most of my failed games happen because I didn't produce enough titanium or energy early enough.

Trade imports (via spaceports) can help with some production shortfalls, but it is by no means a replacement for having lots and lots of mines. The problem of depending on trade imports for production (convert a surplus in one resource for another) is that it's inefficient. You're spending a turn to do the conversion. Unfortunately, at this difficulty level, each turn is crucial! Furthermore, in mid and late game, you're likely to use most of your imports on space projects.

Lastly, science production is also important, but only to a point. You'll want enough for the buildings that provide more project/card options, as well as to unlock certain technologies. I often find that I have a large surplus by end game, which I usually convert to other resources when I get a chance.

2. Expansion/Growth
In order to have lots of mines, you need either a lot of cities (which mean food AND water), or hordes of robots. Either work, and which strategy you go with largely depends on the projects you're offered. I find that I often end up with a mix of both: one mega-city that's huge on robots and has access to lots of nearby resources, and then a couple of other specialized cities (focused on food or as a dumping ground for science buildings, etc.).

Also, don't sleep on the Rover Exploration Center or Exploration Satellites projects! At 14 and 16 resources respectively, they aren't cheap, but over the course of a long game and many explorations, they'll easily pay for themselves. They are especially important for the times you have a leader whose power you want to spam (instead of exploration).

3. Project/Card Options
In a game that's heavily influenced by luck, one way to mitigate this is to have lots of projects/cards to choose from each turn. Having a few Research Centers (+2 projects proposed each turn) helps a lot, especially mid-game when you really need certain buildings or space projects to appear. A Development Center (+1 extra project to pick, +2 capacity for your deck) is nice as well, though I usually don't need more than one.

I've found that taking advantage of certain leader or technology powers can get you past the dreaded mid-game hump. Consider this to be the "special sauce" or maybe even the "win condition" that pushes you ahead just enough to victory. Here are a few examples that I've taken advantage of:

Reverse Engineering
This tech converts ditching a project into support income. If you can combine this with ways to get lots of projects (such as the Eureka leader power, giving you ALL the projects that turn), it can generate just enough support to get through mid-game. While it doesn't scale that well at end-game, by then you should be far along with your terraforming goals.

Lightweight Hull Structures
This tech doubles tritium to space projects. This is incredibly efficient! It saves both resources AND time! This is especially useful for space projects that import water and raise the ocean level, which have pretty modest tritium costs. I've saved several games because I was able to reach a new ocean milestone just in the nick of time. Of course, this requires decent tritium production and luck in getting those projects.

Henry Carnegie and CO2 Imports
This power raises both atmosphere and heat by 4 each time. Spam it all 10 turns he's available, and that's 40 heat and 40 atmosphere. That is enough to get you the first heat milestone and most of the atmosphere one! The downside is that you can't do anything else, so hopefully you've done a decent amount of exploring by then.

Hope O'Malley and Culture Festivals
4 waters for 60 support? Yes please! Granted, this only scales well in mid-game, and only works if you have a decent amount of water to work with. But in the right situations, it can really save you.

Antti Vanhanen and In-depth Survey
For a small amount of energy, you can permanently upgrade a resource deposit size. Also, you can currently do this on a mine you already have, by deleting it, using the power, and then rebuilding the mine (though I wonder if that might be patched out in the future). Over the course of a 60+ turn game, doubling or even tripling a resource deposit is a huge deal.

There are likely other leader/tech synergies that I'm missing or haven't discovered. Feel free to share what's worked for you!

It's important to mention that these combos/synergies are a "nice to have". They are NOT the cornerstone for winning at this level. You absolutely need to have a solid production base, good city/expansion growth, and continual terraforming progress. I have lost many games because while I had some fun tech/leader powers, I didn't have enough resources to back them up.

It should be a given, but I'll mention it anyway: you need to be maximizing every move you make. That is every building placement, every explore option, every bacteria/plant/animal selection, and so on. For example, I usually space out my population and food buildings, knowing that I'll plop down a building with adjacent bonuses later. Got a building that doubles production with high elevation? Try to make that happen, even if it means moving other buildings around! I usually have a calculator on-hand to help crunch numbers and estimate how many turns I have left. Is the game going to end one turn before my next terraforming milestone? Okay, I'll sacrifice a leader power on exploration, so I can get just enough support to last one more turn.

If that type of obsession just doesn't interest you, then playing at max difficult probably isn't for you. At the easier difficulty levels, you can definitely be less efficient, or even play "sloppy". Not so much at max difficulty however.

Support-only Buildings
I'm not a fan of buildings that only generate support, such as Luxury Workshop (+10 support income). Sure, +10 support is nice, but 16 silicon and 8 titanium isn't cheap. It's also taking up a precious building spot, which could be used on any number of things (such as production, project/card generation, adjacency bonuses, and more). Same goes for external resources that general support, though they tend to be a lot cheaper. If you have ample resources and locations, then sure go for it, but don't let these buildings be your primary goal.

Complicated Buildings
I'm generally not a fan of the buildings that have some complexity to them, such as Load Balancing Station (+1 power for every 4 buildings that cost power) or Composting Facility (+1 nitrates for every 3 population). It's not that they're bad, but you should be careful of planning your city entirely around them. If you get one of these projects, and you happen to have a city that's a great fit, then sure go for it! But don't try to "make the synergy happen later". One exception to this rule: robots. You will generally have a city that's big on robots, so I do tend to save (and use) the buildings that have big robot bonuses.

Avoiding Any Negative Expectations
Early on, I played too conservatively, avoiding any expansion that would generate negative expectations. This is not a good idea. Resource production, especially if it's for a titanium mine or a high-elevation spot, is worth the -1 hit. A winning game may last 70-80 turns, so at most you could generate -70 to -80 support, which is nothing in the grand scheme of things. Granted, you shouldn't go wild doing this, since doing this many times quickly adds up. Just don't be afraid of sometimes having negative expectations, especially since there are rare projects (like Bus Routes) that will also mitigate them later.

Here's what a typical Utopian+++ game looks like:

Early Game (0-20 turns)
Always be exploring! It's important to see what's around your first city. Hopefully you've got at least one source of titanium. You also need the resources (and occasional random discovery) from exploring to build your first resource production buildings. You should have at least one Science, Power, and Food production going after your first few turns.

Mid Game (20-50 turns)
This is where the dreaded mid-game hump happens. Expectations start to really ramp up. If you've made enough progress on terraforming, the milestone rewards will keep you going. At this point, you ought to have at least one or two additional cities to help with resource production, as well as where you will park Research and Development Centers (additional projects proposed and to hold onto).

Late Game (50+ turns)
If you've made it this far, congrats! By this point, you have finished numerous terraforming milestones, and spread quite a few plants and animals. This is where I'll actually focus on the scenario's goals (resource production, space projects, etc.). However, don't fall asleep at the wheel. There's still a bit of danger, as you don't have terraforming milestone rewards to count on anymore, and the expectations will continue to ramp up. While I've had a few games where things went so well that I had no fear of losing, there were others where I had to race to complete the scenario objective, before I got overwhelmed.

Even if you follow all the tips and strategies here, you're not going to win most of the time. The developers have said that expert players should still expect to lose most games at the highest difficulty level. This makes Terraformers less like other strategy games (Surviving Mars, Civilization, Stellaris), where there is less randomness and each game should be "winnable" if you have the right skill/knowledge. It's more akin to rogue-like games (Slay the Spire, Deadcells, Rogue Legacy), where success lies a lot in the projects/leaders you're given, what resources are around you, etc.

Personally, I find this quite refreshing, especially since a game of Terraformers tends to be on the shorter side. If I get a bad start at max difficulty, I generally lose pretty quickly (30-45 minutes), so then I'll chalk up that loss and move on. But I realize that type of play style may not be for everyone, and it might be jarring for folks who expect to "win" every game.

Hopefully you find this guide useful! As of this writing, the game is still in Early Access with a lot more updates on the way. I'll try my best to keep it updated, but I do hope that many of these strategies will continue to be viable well into the future.