Even today, Unreal Tournament looks gorgeous on full graphics settings, despite the 5 years since its original release. Not only is it still a strong competitor with modern titles in terms of graphics, its gameplay still holds up nicely too. It is the very definition of twitch shooter, and to play it with anything other than a precise laser mouse is a sin. The weapons are well balanced and fun, the maps are colourful and varied (the highlight being the low gravity skyscraper rooftops map), and there are a good number of gameplay modes.
However, on the negative side, the single player mode is a tad monotonous, and for a game that's meant to be played against real people, the online community isn't quite what it once was, which is what tends to happen five years after a game's initial release, but online matches are still smooth and fun as ever, when you can find other players.