Ammo itself is fairly scarce, only certain enemies drop ammo and only late into the game, otherwise you'll just have to find it scattered around. The biggest problem to me is that the weapons don't feel powerful, again likely a product of the difficulty setting, but when the weakest enemies can take 4 shotgun blasts practically at point blank range then there is a huge problem with pacing. Nothing in the game feels like it promotes a cohesive gameplay intention. teammates obstruct your path, the environments are mostly narrow corridors filled with clutter or general design problems that will lead to you getting hit.
You as a character are incredibly slow, your A.I.
The gameplay however contradicts this, on General difficulty enemies will shred through your health and armour, some enemies will charge at you and pretty much 1 shot you, the game at this point is suggesting that it expects you to be moving around, jumping, dodging, strafing to avoid enemy fire but this is not complimented by the other gameplay elements. everything is pointing at this trying to be a more modern tactical shooter where you bide your time and play it carefully. teammates, the game gives you an assault rifle with a scope, medics tell you to take cover etc. The game frequently has you working with A.I. Quake 4 feels like it took the criticism from Doom 3 and tried to retroactively apply it to the formula they were stuck with and as a result it feels like it can't make up its mind what kind of a shooter it is. Even though a lot of people didn't like Doom 3, I liked it, feeling it did enough to stand on it's own, but where Doom 3 succeeded for me I feel Quake 4 failed. It runs on the same engine as Doom 3, and is pretty much what Doom 3 is to that franchise, a step away from its roots to a more linear, cinematic experience. Part of me thinks it's rather cool how they continued the story this way, the other part of me thinks it was unnecessary. Quake 4 is a direct sequel to Quake 2, you play as a different character but the story picks up right after your character in Quake 2 defeats the final boss there. I played the game on "General" difficulty however and it was such a horrible experience that I barely managed to push through the game and that has to be reflected on how I rate the game, if only to dissuade others from playing the game on this setting. To a degree I feel somewhat bad at rating Quake 4 so poorly, the reality is it's not entirely a bad game, a misguided game perhaps, but it's not bad.