For any fans of Turn Based Strategy games, I strongly recommend Galactic Civilizations II. The Ultimate Edition is available on Steam, Impulse and of course Stardock's own website. The best part of it is the surprisingly good AI and the awesome customization options, which the AI also uses. Everything from the tiny details of game setup to your space-ships are fully customizable. It is a TBS game like Civilization, but set in space. Needless to say, research is a very important part of the game. Fall behind and your ships will be obliterated in a single blast of the Black Hole Eruptor. Or your planet itself might be exterminated by an appropriately equipped ship. Use small hulled ships in large numbers or huge capital ships operating alone. Add more engines to a ship at the expense of a few weapons/defences and you have a very fast attacker/defender. Or go the opposite route. Specialize in one of missile, beam or cannon line of weapons or diversify your weaponry to avoid the enemy AI designing ships to counter your specific choice of weapons.
A very fun and addictive game, and by today's standards, it has very low system requirements. It does use multiple cores, and the AI turns don't take much time, unlike Civ. I love it as much as Civ.
*store.steampowered.com/app/202200/
