It boasts some deffinite improvments on previous installments in the series, but also shows a few fatal flaws.
This is by far the most innovative and deep game in the series. The campaign map, and all the elements that drive it, have been overwhelmingly built up. The new agents (merchants, priests, princesses, ect.) provide a whole handful of new ways to go about the expansion of your empire. Diplomacy has been improved to near perfection. And the way that the papal states and the pope interact with the Catholic factions is vastly more deep than the Senate and it's doings in Rome: Total War..Also, with a whole new chunk of the world to conquer, and with around 200 unique units and around 20 factions, Medieval 2 has a nice bloated gut full of refreshing content.
On to the sensual appeals of the game. The graphics (though they come at a price) are a splendid contrast from that of Rome: Total War. The landscape, the troops, EVEN THE CAMPAIGN MAP looks infinitely better than before. The second sensual appeal: sound. The sound in this game is AMAZING. From the music, to the accents, to the war cries of troops charging into battle, to the explosive cracks of gun and cannon fire, all simply wonderful.
Now I did imply that the game has a flaw or two, so I might aswell get to that. The game's single biggest (perhaps only) flaw is the battle map A.I., it's arguably worse than the A.I. in Rome: Total War. The problem isn't very noticable early on in the game, but later, towards the end of the campaign (once gunpowder becomes the dominant force on the battlefield) it becomes almost impossible to ignore how easily a row or two of gunmen mow down an opposing army who can't decide what formation to take or how to attack you. The opposing riflemen may start to charge you, then fall back deciding it best to skirmish for awhile, then they'll charge you again and route before ever reaching your lines. Opposing infantry line just stand there and let you mow them down while their own gunmen try to figure out what to do...And the enemy's cavalry seems to have completely forgotten the value of flanking your opponent....And when it comes to siege battles....Your enemy still doesn't seem to grasp that standing right infront of your walls, asking for an arrow through the skull, isn't how cities and castles are taken...This kind of Artificial stupidity has allowed me to win several battles with only 4% allied casulties, and as high as 98% enemy casulties..
All in all...The A.I. makes battles in the late game hard to enjoy unless you really hold back on the enemy...
Even though the A.I. is the equivalent of an enormous and hairy wart (5.9 mm in diameter) on the lip of the most heavenly female face ever gazed upon by a mortal man, the game still offers a satisfying degree of content.