UT2004 has lots of gameplay modes, maps, and mutators. The bots are damn awesome if you don't want to play online. I find Halo to be dull and mediocre. There are about 5 or 6 vehicles in UT2004 and are damn awesome. Onslaught is the best because those vehicles are very useful in them. If you didn't thing the original UT was great (you're one of the first people to ever say that ) then I don't think you'll be too entralled with UT2004. I mean it's improved greatly but its still the same kind of game, pure multiplayer. I mean...you can get both games, buy one and get the other through different methods.