Some of my favorite games:Distant worlds: Great gameplay coupled with epic scale epicness. I would surely pick it up! And I have, and it is quite enjoyable.As mentioned earlier, Haegemonia is a fine candidate. You might want to add some extra flavours to it, like star wars-ness through vector prime and more epic maps and mechanics through prophecy.Video: (shameless self advertising

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If you want to go back to the 90's, a great 4X game (and one of the first RT4X games, if not the first), is the imperium galactica series. Especially Imperium Galactica 2: Alliances is very good! With some patching, it'll work fine even on newer computers. Think of MOO in realtime

Also, light of altair is a fine 4X game if you like some more basic games (but not less challenging!).lemme browse further through my installed games list.Ah yes, I run here into homeworld 2. Add the complex mod to that, and you'll have an outstanding game! Video:
And we delve deeper into my games list, and we hit some more games...I would recommend watching Sword of the Stars II. If it gets some more bugfixes, it would make one of the most epic 4X games ever made

I own it currently, so can keep an eye on it for you.If you want an MMO feel, try beyond protocol / after protocol. Also a very outstanding game!Galciv II is a nice game

I did like the concept of Star Ruler (I beta tested it), but as said earlier, it should still be considered a work in progress. Some mods fix the most annoying parts of the game though.Soase Rebellion, hmmm, what to say about that. It's a fine game, adds quite some stuff. But for me it kinda feels like an expansion pack in its current state (yep, I play the beta of it). If it would drop in price a few bucks, I would recommend buying it though.So that quite sums it up

Enjoy many, many hours of gaming.Oh before I forget... I found another ancient game in my games list... It's Far Gate! The game is hardly known about, but it's a very well-made game, and one of the first successful indie games. You'll be able to find it on the interwebs. If not, I might be able to give you heads up where you can get it.