AI War 2

I hesitate to call this the Dwarf Fortress of RTS, but that's the most apt comparison I can make.
AI War II is extremely dense in information presented to the player, as well as strategies and mechanics available to both the player and the AI. It is not a game someone can just turn on willy-nilly and break the AI in five minutes. It is a commitment, and I find this to be both its greatest strength and its biggest flaw.
AI War II does not shy away from giving the player a consistent challenge no matter the difficulty level. The AI is always stronger than you and can destroy you whenever it feels like it. The idea is to pick your battles and strategically weaken the AI so that you can win before the AI decides it doesn't want you to. This adds vast strategic depth, but can easily instill a crippling case of analysis paralysis in new players. It will also likely turn off any players that try coming into the game looking for an easy victory. You should look elsewhere, for it shall not be found here.
However, if you are willing to commit and learn the games secrets, you will find a richly rewarding strategic experience rarely seen today. This is a genuine labor of love, and it shows. If you so choose to accept this mission, then start a campaign, learn a mechanic or two, take your lumps, and repeat the Dwarf Fortress creed:
LOSING IS FUN!

It was quite intimidating seeing the UI at first, but after the 20-30 minutes of OPTIONAL tutorials, I felt much less intimidated. There isn't a whole lot of lore, but what is there is great! The game isn't fast paced which i appreciate, the ability to pause gives you however much time you need to think about any decisions, and there isn't a ton of micro that keeps me away from other RTS games. I appreciate that the wiki is literally accessible from the menu, complete with strategy guides and every bit of info you could need! The unit variety is pretty good, with many different fleet setups possible, and the models are genuinely impressive, my favorite part of getting new units is just seeing the models! Another strength of the game is how customizable the game is, there are enough options to make your head spin, just about any setting can be changed to your liking! I also appreciate that many of the mods are also just in the game, waiting to be enabled if you are interested, i appreciate when the developers give tools and visibility to the modders, who add quite a bit of free content for everyone! I bought all the DLC and i enjoy all that they add, and of course the options let you only use the parts that you want to see! The other species have cool asthetics and mechanics to add, and with all the DLC there are many factions to choose from to make each game you play quite different, and the skill floor is very high. The depth is impressive, the AI seems to make good choices, and feels very fair compared to other 4x games on higher difficulties. Highly recommend to anyone that enjoys the theme and can get through the tutorial, after the tutorial the UI won't be intimidating and you can enjoy the struggle against the AI or powerful aliens and other oddities!

I haven't seen much of the depth and breadth of this game yet, and so this is heavily subject to change, but here is a review primarily about my criticisms. (I have since played about 120 more hours, and will now add my revised thoughts in addendum to the original review. Basically, the more I played the game the more fun I've found myself having!)
Firstly, the AI seems weird. Even when it is moments from destruction, it will boldly announce you have 0% chance of defeating it and considering what it can do, it really won't do a whole lot to stop you. I know this is to make the gameplay more playable because if it actually went all in once it realised it was about to die you'd certainly be crushed, but it seems weird that going too far away from your controlled planets incites a much greater response than a direct attack on the AI overlord itself. Maybe this changes on higher difficulties, I don't know yet. (revised opinion: yeah, still weird... but to be honest this is a weird criticism in hindsight, the only reasonable way to change this is to make the AI reserves weak or imply the overlord has some kind of canonical reason why it can't mobilise all its forces)
In the first AI War game, it seemed a bit more understandable to me - maybe this isn't the intended interpretation but it seemed like the galaxy you operate in was but a tiny piece of the AI's true extent - it felt more like you were trapped under the AI's toenail and the goal was to detach that toenail and run off with it. The lack of extreme response could be justified then as ultimately it's not even a big deal to the AI if they loose the galaxy, but while I know canonically the AI isn't restricted to just the galaxy you play in in the second game as well, the game doesn't really do much to show it, and it feels like you're actually taking down the whole thing. Making its relative unresponsiveness kinda immersion ruining.
(revised opinion: the AI overlord does actually function as a warp gate to connect it to the rest of the AI's empire, and this galaxy is a backwater world the AI barely cares about. I do feel like the game doesn't make this very clear though.)
Secondly, I will first say the game leans heavily into the concept of "strategy over tactics", micromanagement of your forces isn't really important other than in making sure they get to the right places at the right times. But this is weird because it feels like a lot of the game was built for tactics. There are a huge range of ships in this game, every game your army will have a unique assortment of all sorts of craft specialisations, many of them having situational crazy attack modifiers or unique mechanics... and that in itself is a great deal of complexity, there could be a lot of depth to battles, but really whatever you choose doesn't matter as long as it fits with the tech you've specced into and you kinda just vaguely gesture "go and kill everything over there" to the large clump of your assorted forces. They automatically decide how far they should engage from and what to engage to make the best out of their properties for you. It almost feels like there's too much variety, most strategy games have a rock-paper-scissors going on with a few things to fill more niche roles, but here there are five hundred different hand positions and any mix of ten of them will do at least alright against pretty much any other mix.
It makes the great complexity in combat between fleets feel kinda wasted, as you just don't see it, it's just a mush of 3d models clipping into each other with neon lights everywhere in a battle where very little player oversight is actually required.
(revised opinion: I have come to understand there is more to choosing the composition of your forces than I initially thought. Battles are mostly a very simple endeavour still, but back when I was playing easier games I put much less thought into many of my choices and just didn't think much about synergies or certain roles much.)
Thirdly, and I guess this links into the second point, your lack of ability to adapt in the way that you can in most RTS games is a bit disappointing, even though I know it is intentional for so much of this to be kinda abstracted away as this isn't supposed to be the focus of the game. In most RTS games, if you loose a big group of forces, you go and look at what the enemy used and try to rebuild new forces with the goal of anticipating what your enemy will bring next time and try to counter it. That doesn't really exist here. Once you have a ship line, that's sort of it. Your fleet got wiped out? Send your flagships home and two minutes later your fleet is back, exactly the same as it was before. You can only seriously change it by altering what techs you've got, but reverting science upgrades just to buy new ones is kinda pointless as really you should already have specced into what you have. Because that's how science works, it isn't to get new stuff but to upgrade what you already have.
(revised opinion: yep. but at least it means your choices matter in the long term and allows the game to be played a lot faster than it would be if you were constantly reorganising your forces.)
Fourthly, after playing the first game, metal and energy just seem too generous. Not to say the game is too easy of course, but managing your metal and energy seems basically trivial in this game compared to the first. You're low on metal or energy? Just spend a small amount of science and get a massive boost. You seem to never really have to cut back on your defences or repairs in order to not have your ability to maintain yourself severely compromised.
(revised opinion: ehh, sort of. This aspect of the game can actually become more important than I thought, you just don't really notice it until you're actually struggling, and tech can only go so far.)
It just feels... simple. The game looks complex with all the stats windows, and is internally a marvellously complex piece of software, but the actual gameplay just feels simple. In my opinion, the developer took the de-emphasis of the more menial parts of the game a bit too far.
(revised opinion: hmm. I kind of stopped caring about this, and due to my not being able to relate to my past self I am not sure what to say to this. But the game is complex enough to be engaging for sure, if you stretch yourself on the difficulty.)
That being said it's a good game. I look forward to experiencing all the variety I'm yet to bring in. There are also a ton of built in mods including one that brings back a lot from the first game that I'm keen to try out, and the game has so many other factions including the DLC ones, many of which I am yet to experience as well.
(I have now experienced much of this. Yeah, pretty neat stuff out there.)

A unique RTS with a toe in grand-strat. It has this completely different model of conquest b/c you can't out-economy the enemy. Instead, you have to look at the map and figure out how you're going to steal power from them while constantly staying under the radar and hiding your true strength so they don't just turn and crush you like an ant.
The map of the galaxy is a puzzle. A tactical and strategic one that bears careful consideration and constant risk-reward assessment which I found to be completely engrossing.
I have immense respect for the developer for making the higher difficulties pit the player against an ever more capable/smarter foe. Demanding more nuanced tactics and resource balancing. This isn't some "just add zeros" difficulty. You'll have to play differently, building on what you've learned, for each and every difficulty you aspire to.
And then there's game-mode modifiers like expert and logistician mode which layer on top of the difficulty levels.
You could play this game for a very long time and never master every aspect of it I feel. I've already beaten it 5 times (from difficulty 4 through 8) and am still learning.

I don't know anything about upcoming Heart of the machine but I'm sure about one thing, it's going to be updated frequently, it's been 5 years since AI War 2 was relased and this madman still update game like it's fresh project.

Much has been said about this game already, but one thing I'd like to add - this is a slow-paced macro RTS/4X that (usually) does not put pressure on you to make decisions NOW. I really like the idea of RTS games but nowadays I find most of them too fast for my liking. This game is slow enough for me to take in the situation and decide where to go, and that is a nice bonus on top of the underdog/guerilla warfare game design that just keeps me hooked.
Great game, if you can stomach the unorthodox UI choices and information overload at the start. Have guides on hand and keep things simple at first.

Did not read the Subvert Super Terminal hack right and proceeded to cause a wave the strength of 1.24k to descend upon me and my buddy's home worlds while all we could do is sit and watch 3 hours of work be destroyed. 10/10 would get absolutely curb stomped again.