C-Evo is a game based largely around Civ II. It is not THE SAME, as civ II, and in fact sets out to solve many of it's shortfalls.
One! It is completely deterministic. There aren't random goody huts, a unit with higher stats will always beat a unit with lower stats, (unless it's damaged/behind a wall etc) and so on.
Two! The AI plays by the same rules as the humans. The human is even considered an AI player by the client. The AI does not cheat, it doesn't look at your maps, it doesn't fudge resource values or unit build times, it is all solid. And don't think this means the AI is a pushover either, it can get surprisingly nasty. (Not that I'd know, I can't even beat beginner, and am terrible at Civ in general.)
Three! Apart from a few fixed units that largely have special abilities, units must be made by the player. Now, this is still a low tech game (made for windows 95), so don't get TOO excited, you mostly just pick stats/abilities, and the sprite alters to fit the layout. War techs upgrade maximum limits for units and skills (such as overweight, which increases armor and attack by one level, without using a "point" for either, but makes it harder to move around), so there's still a sense of progression. For instance, you litterally can't upgrade a unit's mobility before you get horseback riding.
Four! You can't gain tech immediately via trade. When you trade for a tech, you get knowledge of the tech, you no longer need the prereqs to study it, and it takes about half the tech points you originally needed to finish research. You also don't gain tech from capturing cities, unless you have a specific wonder called the statue of Zeus. (which incidentally is an AI agression MAGNET, I have seen the statue of zeus change hands like eight times and I've only played two games. The statue was destroyed in both games, natch.)
Annnnd
five! A spaceship requires scarce Modern Resources, that are only available after you research mass production. As in they only become visible after you research it. They are always on terrain called deadlands, which cause damage to your units if they step on it. (there are ways around this, but they largely invalidate the resource on the deadlands I think, but they work for deserts and artic tiles which also damage units) On any given map there will be 12 deadlands. 6 of them will have resources, 2 of each. You need all three to make parts. So in otherwords, even in a "peaceful" game you're probably gonna have to duke it out at one point or another if you want to win.
Now, for one fairly major problem, it doesn't have (easily accessible) internet multiplayer. You can play it over LAN or hotseat it, but if you want internet internet multiplayer you're gonna have to do some finagling. No, I don't know how. I'm sorry. Luckily, unless you're just the best civ player ever, the AI will almost certainly give you a run for your money in any case.
STUFF TO KNOW (or that I forgot to mention)* If you don't know what something does or should be doing, shift+left click it! It'll open up the encyclopedia/stats page for it. Game doesn't tell you this for some reason.
*The first thing you want to do with any town other then your capital is build a town hall (the palace acts as a town hall for the capital), a town hall enables you to gather trade, period. Or maybe it's only one trade per square. I forget. Point is if you want a town to pull it's weight financially the first step is a town hall.
Thanks to Akura for these!
1. NEVER trade techs to "friendly" nations(nations you have a friendship treaty). They'll simply declare war on you once they've got everything out of you.
2. Expand. Expand hard. To prevent tile sharing, you can build a city one tile outside your borders(there's an option to show borders)
3. If a city is above 3 population, and isn't growing due to not having enough food, build a settler/engineer. Settlers take 2 population from a city, and under most governments take one food. Use that settler to start irrigating.
4. The Great Wall gives a City Wall to every city that has a land connection to the city with the Great Wall. That is, if a ground unit can walk there, the Great Wall goes there too.
5. Cities with a canal connection to the sea are considered coastal(I think. The sea might have to be within the city area, but not neccessarily adjacent to the city) for unit construction(possibly buildings, too).
6. Most Wonders are very useful(except Manhattan Project, since there's no nuclear unit in the vanilla game). Especially useful: Colossus(all other Wonders 25% cheaper), Newton's College(double research if Monarchy), the bullet-train thingy whose name is too long for me to remember(free movement across railroads, as per Freeciv), MIR(reveals the map, gives contact with all nations, and gives vision and nation information to everything for one turn). (Addition by me: Wonders also add 2 happiness to cities, along with not having upkeep (some of them anyway, maybe all of them), so if you're looking for some happiness in a city but don't want the hefty upkeep of a theater then there ya go.)
7. Submarine transports. The AI seems to neglect Radar/Sonar, or maybe they never researched it, I'm not sure.
There are also other minor changes. The base is still clearly Civ II, but a lot has changed. That honestly pretty much covers it, so if you'd like to give this a shot, mosey on over to
this place. There are some screenshots there, but again, it's not exactly amazing graphically.