Computer opponents in 4X are usually pretty dumb. When a game like Civilization tries to make them think and act like humans, they’re about as convincing as two kids in a big coat trying to pass as Queen Victoria. Civ 6 has avoided this problem by instead focusing on making each AI leader an interesting challenge for a human player to unravel using clever systems like Agendas and the new casus belli civics, creating the most intricate and enjoyable diplomatic climate we’ve ever been treated to in single-player Civ.
I talked about how game-changing AI agendas were about the biggest new features, but it bears repeating. In previous Civ games, AI leaders were programmed to act like a friend playing with you on LAN. They’d play to win, entertain mutually beneficial alliances, and often backstab you out of nowhere if they felt it would help their chances of victory.
When a real player declares a surprise war on you and plunges the world into chaos, it creates an entertaining rivalry. But when a computer player does it, it usually seems unfair—especially if you feel like you did everything “right” to make those duplicitous lines of code like you. We understand people being jerks and betraying us. But we understand pre-coded systems have to have rules. And we want to feel like we have the agency to play by those rules and achieve a desired outcome.
AI agendas fix this by creating a more comprehensible web of relationships with exposed knobs and levers. At the same time, it avoids the trap of making it really easy to stay best buds with everyone forever. China gets jealous when another civ builds a wonder, so I have to weigh whether the science bonus from the Great Library would be worth the economic cost of a war against them. When Germany's Barbarossa calls "dibs" on every city state, I know immediately that we’re going to become foes even if we’re not in competition for land or resources. I’m constantly making interesting decisions between restricting the paths my empire can choose or letting relations with another leader sour. And that’s not even bringing the randomized, hidden agendas (which give a new, very important role to the espionage system) into the conversation.
Why we can’t be friends
Civ 6 has also followed games like Crusader Kings and Europa Universalis by implementing casus belli: reasons to go to war. These are unlocked by civics on the new, culture-based tech tree, and lessen the diplomatic penalty you get for warmongering if you have a good reason. Unlocking Holy War allows you to rebuke someone who converted one of your cities. Unlocking Colonial War makes any civ a certain number of techs behind you fair game. You don’t need a casus belli, but going to war without one requires you to either launch a Surprise War (which is likely to turn the rest of the world against you), or issue a formal Denouncement and wait five turns—at which point, your opponent probably knows what’s coming and has prepared their defenses.
This system not only creates a context for war and interjects some historical flavor relating to why real-world conflicts break out in the first place, but it weaves in with the agendas to create a web of friends and foes that helps the game of empires feel more complex and realistic. The other leaders aren’t trying to act like your flesh-and-blood buddies. They’re acting in the way that will give you the most enjoyable, challenging, and interesting experience as the sole air-breather at the table. And that design philosophy is extremely refreshing for someone like me, who spends the vast majority of his time in singleplayer.
As much as some players would like to believe that 4X is about universal symmetry between sides, it’s really one of the genre’s greatest myths. I’d love to see more strategy devs show recognition that single and multiplayer are completely different animals, and AI should be designed around making the former the best experience it can be. What’s fun and engaging for a solo conqueror is going to be very different from what makes LAN brawls great. And it’s the mark of a great game when each experience is tailored to be distinct, but both perform admirably in their own way.