XIII is a unique game, effectively it is the father of both Far Cry and Borderlands. And it can now be enjoyed worry-free.
The good plot of Far Cry bears eerie similarities to XIII, not in the tropical island setting but in that the hero wakes up with amnesia on a beach (with the roman numeral XIII tattooed on his arm) and than has to feel his through an obsessed assassin and a pack of ruthless mercenaries. The race is on not only to stay one step ahead of his conspiring enemies but also to discover his true identity.
This was the first major PC game to sport the daring comic-book look of cel-shading. Unlike Borderlands, which I found to have done so only halfheartedly, XIII pulls it off with gusto as the comic-book graphics are accompanied with comic-book exclamations and comic-book picture-in-picture format, offering a unique experience. It is like playing inside a comic-book - and it is great fun!
Now, the game is not without its flaws. It has a checkpoint saving system that makes it much harder that it should and the guns (probably to stay faithful to the original comic-book the game was based on) look rather underwhelming. However, although not perfect, this a game that you will enjoy playing and you will remember it for years.
When XIII came out in 2003 I went nowhere near it as it harbored an overzealous DRM scheme (an early version of Tages) that blocked disk drives from working properly and refused to launch the game if you had any form of "suspicious" software installed (let's just say that Ubisoft considered NERO to be...pirateware!). Eight years (and a couple of class-action suits) later, one can enjoy the game DRM-free (just be careful which version you choose).