I have played every game in the main series. Civ 1 was amazing, a great breakthrough in gaming history, but from the perspective of 2018 you probably can skip i

I have played every game in the main series. Civ 1 was amazing, a great breakthrough in gaming history, but from the perspective of 2018 you probably can skip it, as Civ 2 is richer and more polished. Maybe because I'm a bit old (sigh), but for me the favorite is Civ 2, and in particular Civ 2: Test of Time, which is even better than raw Civ 2. It has the particularity that it has an optional "extended game" where the tech tree goes further into the future. Instead of stopping developing technologies at the present time, you could develop cyborgs, plasma weapons, force shields, and stuff like that. And you could go to Alpha Centauri, where you would find a different map and an alien civilization there. IMHO no game in the series has done the future so well. As a bonus, Test of Time lets you play the original Civ2 game with improved graphics if you don't like the extension, and it also includes space and fantasy scenarios that are not bad at all. Why almost no one knows that game? Probably the reason is that it was panned when it came out as it was widely seen as a cash grab. It came out a few years after the regular Civ 2, and it didn't feel good that they were charging the price of a full game for what was essentially an extended remake of the game people had spent their money on previously. But now that we are in 2018, who cares about that. In my view it's the best game in absolute terms. Civ 3 introduced many new concepts, but some of them didn't worked too well and the playability was not too polished IMO (culture, and absurd lack of basic resources like iron and coal, I'm looking at you). Civ 4 continued the trend of Civ 3 but polished it, nerfing or buffing mechanics that were unbalanced, and it is the game I would rank as the second best of the series if you don't want to play Test of Time. Civ 5 made some quite radical changes mentioned by other commenters, while it's still great I personally don't find it as fun as the earlier games. And the same goes for 6. Also, RIP Civ World. Not quite a Civ game, but maybe the best Facebook game I've ever seen. It would have been great if they had bothered to solve the bugs. Some of us still remember you.