AI War 2

It is hard to recommend to the people who might just read the tags for this game, if you do you won't have the right mind set of what to expect. It's closer to a stealth mission with limited units in an RTS. If you go in blowing up everything and increase your threat level too much you will die spectacularly.
You must plan and have a good reason for taking out certain bases, falling back to defend occasionally until you are ready to take apart the enemy at their core. Fail to get it in one or two attempts and they will be knocking at your door with units you can't possibly stop.
It is no exageriation to say if you set the difficulty too high or set more than 1 AI it might be impossible to win. I'd highly recommend no higher than a single AI at 2-3 until you have a few games under your belt and know what to expect.
Remember that you are always the underdog and the odds are stacked against you.
The learning curve will be massive.
My only complaints would be the neutral factions taking out bases counting against your threat level and the massive CPU usage if you set up the game too big or complicated.
If none of these things have made you run away you are the person that I would recommend this game.

This game can be summarised as roughly:
A strategy game where you plan your next steps like in a puzzle, where the progression in a is similar to a roguelike, and the difficulty and playstyle of a session can be adjusted extensively to whatever degree you desire.
Make sure you read the things the game tells you, and you'll get the hang of it quite quickly.
If you want an easy and relaxed experience, you can have that. If you want it ridiculously difficult - you can have that too.

Here’s a curious fact: look at the achievements and you'll quickly notice something funny. Only about 20% of players have unlocked even the easiest ones that pop up after ten minutes of gameplay. That means 80% of you bought this strategy gem and immediately decided: "Nah, not today, I have 200 other unplayed games anyway."
I get it. This isn’t exactly the kind of game that greets you with cinematic explosions or eye-candy visuals. The graphics are functional, like my microwave, practical but not winning beauty awards anytime soon. And yes, the UI might initially give you that "did someone spill spaghetti here?" feeling, but trust me, it's quicker to figure out than it looks, especially with the built-in help system ready to guide you (assuming you actually read it).
But jokes aside, the developer has poured genuine care into continuous improvements and expansions. Behind the awkward first impression lies strategic gameplay that can be deeply rewarding if you give it a fair shot. If you're among the majority who bought it but haven’t played yet do yourself a favor, spend at least two hours and see what you're missing. If you don’t own it yet, wait for a sale. It's definitely niche, but it's the good kind of niche.
Just remember: clicking "buy" won't magically grant you achievements. Trust me, I tried.

It's honestly a crying shame that a game this original and distinctive should have lost money and disrupted the lead developer's life. The strength of his design is apparent in how willing a core group of supporters have been to keep the game updated half a decade after its release. I don't play this as often as I should, but its rhythm is like nothing else on the market. I blame the decline of the indie-games press between the release of AI War: Fleet Command and its sequel, but that's neither here nor there.
Play this if you want a game that only gets harder and never lets up until the great climactic final battle. The expansions are wonderful, but even the vanilla game has much to love about it. You will have to get over some cheap bits: The graphics are not top-of-the-line, and you'll never want to hear "It's either death or success!" again after three campaigns. But it's well worth the effort to acquire this taste. One day I'll go back and get serious about this game.

I am very fond of this game, that is an engine + lots of contents to tune the challenge in very varied ways. I buy a DLC from time to time as a support to the (almost) solo dev, and I end up enjoying the new content.
It works great on my HP Envy laptop, which is rudimentary gear. Congrats to the dev(s) for optimizing so well the engine, with thousands of units taking decisions and performing the pew pew smoothly.
The game is best played as intended : the player has a tiny fraction of the might of the opponent AI, yet must defeat it with calculated moves. Stacking too many factions on the player side looses the fun, and might cause some slight performance alteration.

Might be the best 4x game ever made and I say this as a person with more than two thousand hours in Stellaris. Its a hard call for me between the two but its definitely between AIW2 and Stellaris. I know I have low hours as of now but I've played almost all of these types of games and I can just already tell.
For newcomers, it skews more Sins of Solar Empire than it does Stellaris. But if you enjoy either of those games, there's no reason you won't love this. They say it has a steep learning curve and I'm sure I can go much deeper, so there's that for people who enjoy that kind of depth, but it should also be a pretty easy learn for anyone who plays 4x games frequently.

This is the Dwarf Fortress of the X4 Space Games genre. The depth of the content just keeps going and if you think something would be fun, cool or nice to add to the game, it's probably already part of the game in some form.
Losing is fun and figuring out how to not lose even funner.