Requires considerable investment, with enormous returns.
The Bad: Unimpressive graphics and sound, rare but irritating glitches and crashes, basic and uninteresting battle system, fairly steep learning curve.
When it comes to historical strategy games, you would be hard pressed to find one as all encompassing, as intricate, and as difficult, as Crusader Kings. Be ye a role player, a history buff, or simply a gamer seeking something that deviates from the norm, Paradox's medieval adventure is definitely something for your consideration. Be warned, however, Crusader Kings is not for everyone, and can be considered one of the greatest "Hit Or Miss" games to grace the PC.
Crusader Kings places you in the role of ruler of a medieval County, Duchy, or Kingdom, and sets you upon the task of building a medieval dynasty to last the historical time period from the Battle of Hastings in 1066 to the fall of Constantinople in 1453. Your success is measured in Prestige, Wealth, and Piety, as well as the sheer size of the realm you bring under your control. Though one may start with considerable power and wealth by taking the reigns of a pre-existing Kingdom like the Holy Roman Empire, England, or France, the true reward comes in rising from a lowly count or duke and usurping the Capets or De Normandy's to lead your own dynasty to glory. Crusading to the holy land to convert the heathens to your faith, ending the schism by returning the Orthodox under the Pope, or simply eliminating the remaining pagans in Northern and Eastern Europe all provide alternate entertaining avenues for your resources which may go to waste at home during times of peace. War with non-Christians is also much simpler as it does not require the player to establish a "claim" on the other player's land titles (which cost prestige) nor does it lower the reputation of the player, which makes his vassals disloyal and wary of his unstable and warmongering intentions. This does become irritating and unrealistic at times, but can be lowered by assassinating a few members of the court as examples of those who resist the ruler's rule. With a bit of tweaking, it is also possible to make the player's own character bear his last name, for those who want to make their indelible mark on history yet more pronounced.
Modding is very important to this game, and marks one of its hidden perks. The fact that paradox cannot seem to match the fan community in its ability to perfect and enhance their creations should not discourage one from purchasing their games for that very reason; the good fellows at the Paradox Community Forums are what truly make Crusader Kings an epic experience. Though great in its own right, the various graphics enhancements, alternate scenarios, utilities (such as the invaluable bride finder), and the mods which allow play as Muslim and pagan rulers raise CK to the next level. Most of the flaws such as instability and inability to play as non-Christians are immediately nullified, and the positive side is made only stronger. This can be somewhat overwhelming to the casual player who is not willing to invest the time necessary to comb the forums for these improvements, let alone spend hours speeding through the centuries to build their dynasty, but for those with the willpower and patience, it elevates Crusader Kings to the level of any PC classic. With a potential, yet flawed, conversion utility to classic Europa Universalis II at the end of the Crusader Kings campaign, the adventure can continue through EUII and through Victoria and Hearts of Iron II as the twisted and unfamiliar world spans 950 years of history.
Crusader Kings is not without flaw. As previously stated, the system of claiming titles and reputation can be come irritating and unrealistic, and the battle system once implemented is based almost entirely upon number of troops, with minimal attention paid to the army's composition. As with any paradox game, instability rears its ugly head, though the yearly autosave can usually offset this. For a casual gamer, seeking instant action and gratification from their games, Crusader King's flaws will overtake any positives it may deliver.
Overall, Crusader Kings does mark one of the best of Paradox's series of Historical Strategy games. The balance of simplicity and detail is unusual from a company known for its love of overwhelming learning curves and detail. If you are looking for a historical game that requires considerable investments in time and effort, or a realistic look at the medieval world, Crusader Kings is a must buy.