Quake 1, Quake 2, Quake 3, ..now Quake 4.
The SinglePlayer at first may seem unimpressive, but as the story unfolds it gets better. There is a twist in this game, and that is to leave you to find out. There are a lot of bosses to fight against, but the most fun about Quake 4 is that even for a linear FPS, the action and excitement is all in the level design, the awesome lighting, atmosphere, smart enemies, and sharp sound that wont bore you.
I have to say, that for the first time a Quake game has me wanting more based on the story. Graphic-wise its like Doom3. It is a Doom engine but even though it looks alike, it doesnt play alike. There's no dark corridors, there's no monster in a closet, and you're not fighting alone all the way through. Sure, there are suprises and enemies pop out of nowhere, but the pace is faster so it feels apart from Doom, or any other game out there.
The enemies have returned, you'll recognize some from Quake 2 but many have new moves, and smarter intelligence now that you swear you're not playing against an AI. Thats the fun part too. The AI keeps you on your toes, and gives you a challenge. Sometimes you'll tag with some of your squads to fight so your not this lone marine vs a Strogg army. The good thing is there's usually a medic or armor marine which you can ask to replenish yourself. For the rest of the times, you're a one man machine just trying to blow off any Strogg you see, or mutated human in your way.
Multiplayer is not so promising, but its fun. It feels like Quake 3 with a better engine. Make sure to update the latest patch since they managed to make searching for servers harder, and the lack of customizations is a no-no.
You'll probably enjoy the SP more than MP. Thats the focus...but why didnt they do good on both so Quake 4 could had been the Game of the Year? Or a game that's on the 9.0 rating mark?
Maybe they only cared about Enemy Territory: Quake Wars coming out soon for multiplayer. Thats too bad. Overall, a good game though.