Do NOT buy this game.
If you like the Crusader games, just stick to Crusader 1 or 2. This game has NO campaign, as well as the same multiplayer system as Stronghold 1, despite coming out AFTER stronghold 2 and Stronghold Legends, both of which had online multiplayer. If that was all there was, then this would still be bad, but not "OH MY GOD NEVER BUY THIS" bad. However, they made some aggravating changes in Extreme that just make the game completely miserable to play. First of all, for some stupid reason, you and ONLY you have access to a power bar that has abilities ranging from HEALING YOUR TROOPS, giving you a free 2000 gold, raining down rocks that deals a good chunk of damage to buildings and kills most units, two separate abilities that give you free units (Macemen and Spearmen), spawning engineers for siege weapons, among others. This type of thing does NOT belong in an RTS, let alone when only the player and not the AI has access to it.
On top of all that, for some stupid reason the army size cap was raised from the sub 1000 it was in the other games (I don't know the exact cap, but I know it was under 1000) to 10,000. So ignoring the fact that this would cause probably even the top end of PCs to lag like hell if 8 players all had 10,000 soldiers, if you are playing against the AI which is likely considering the fact that this game has the Stronghold 1 multiplayer, the AI is so braindead stupid that it will just send troops after troops after troops after you, never building it up and letting you build up your own army. And between that and the broken ability bar, AI matches are completely free.
How is it without using the ability bar? Bullshit. Map design seems to be built to make food production nigh impossible (there's no hunters huts as far I can tell, and there's very few oasis----the only places that dairy farms and apple orchards can be built, across the maps). On top of that, the AI is so aggressive that they will try to destroy whatever buildings you DO try to build on said oasis, because they need them as well.
And somehow the most asinine design decision they made here, they made special variations of barracks and the mercenary posts that infinitely spawn troops. I had one game where I had almost 3000 of a single unit because of this garbage. You can destroy your opponent's, however as far as I know, the AI will never try to destroy yours. So once you've destroyed your opponent's with say, the rock ability, you basically just win because they spawn troops at such an absurd rate that no computer would ever be able to keep up with it without cheating or using the same system. This is also problematic because this completely takes away from what made this series great ---- managing food production and weapon production to BUILD UP an army over time.
And if you try to team up with the AI, they constantly harass you with requests for goods, and if you try to request goods from them, more often than not, they will say no.
And for the LULs, I decided to see what would happen if I tried to disband a huge amount of troops. My game froze, and basically crashed. We're talking about 1000+ units.
I could go on and on about how shit this game is, however I've covered basically everything.
Don't buy.