It's graphic style may be the first thing you notice and the last thing you forget, but it has much more to offer . . .
The Bad: It has a great story right up until the end were it manages to ruin it.
The style of the graphics will probably be the first thing you notice when playing the game; It looks and feels great. If you get a head shot with a sniper rifle, crossbow, harpoon gun or a throwing knife, or stab someone with a harpoon or throwing knife, you'll get a three stage, comic-book-style close up, which not only congratulates your prowess with one of the above, but also looks really, really cool!
If you shoot someone and they fall from the top of building (etc.) then you'll either get another three stage close up or a much larger box will give you video of them falling off. If the game wants to bring your attention to something It'll do another larger box quickly, or if it wants to bring you're attention it'll do several boxes that are in between those to sizes. All these movies and frames look really awesome and embellish it's cell-shaded, comic-book style.
The story is great... until the end. You're trying to uproot a conspiracy at the same time as finding out who you are. It's really enjoyable and should keep most gamers enticed by and focussed on the game. Luckily it's only the last level that messes up on the story front.
The sound effects are fine, nothing to shout about, what's really cool though is the graphic accompaniment to the sounds, if you kill someone loudly then it'll come up with a 'nooooo' or similar. It looks really cool and reinforces its comic-book-style-e-ness.
The weapons set is great, you can take people on with a low power pistol (with or without silencer (depending on the mission) a revolver, a pump-action shotgun, a double barrelled shotgun, an assault rifle and what looks like an uzi (and more). You can even dual wield the pistol or the uzi (you can't mix and match) once you have acquired the skill. However, you can also disable you're enemies with ashtrays, beer bottles, chairs and brooms amongst other things.
I mentioned above the dual wielding skill, there are actually several skills including silent walking and longer breath (for when swimming. Some of these skills are noticeable and others are not, it won't even tell you when you've acquired them, you just have to check the skill page regularly.
The multiplayer is enjoyable and should last you between two and ten hours to get bored of it, depending upon who you play with. This has one of the best multiplayer sections on the gamecube, and if you only own a gc or a Wii it's one of he best mp experiences you can get.
If you want a decent FPS or a comic book style FPP experience then XIII should definitely be on the list of maybe's; it's compelling graphics, enjoyable gameplay and, for the most part, its story stand head and shoulders above many of its competitors. If this is one that you've missed make sure you do go back and play it as it will provide hours of fun for a bargain price.
MB