I got this game after being promised a 'single player'.
Yes there is a campaign... And you can play solo with bots but daaaamn that AI is so ♥♥♥♥♥♥♥♥.
You have to lead every time, they don't go where they are needed. Also if you enter a room often somebody stays outside where they are an easy target. AI doesn't know how to use melee or throwable weapons either and if you're further then 2 meters away chances are it will take them a long time before they get those nasty zombies off your back. Also you are the only real victim for the special infected as you lead the pack so if you walk to fast (or if you walk at normal speed and they get stuck somewhere or wait for you to walk further then 5 meters) chances are you'll take 60% damage when the first special zombie attacks you. Don't forget that the jumpers don't actually have to fly towards you to hit you, they teleport at the moment they get off the ground.
I could go on for about an hour about everything that is wrong in this game, like how fire spreads through a brick wall without being visible beyond the wall. You start a fire inside a room, outside the room a zombie runs past and suddenly it bursts into flames and it does more damage when it approaches you. Or how when you pick up 2 identical guns they become the standard gun + a glock. Or how you sometimes can't pick up the same pistol twice. Or how sometimes when you switch the guns for a melee weapon you only drop one pistol so you have to look for the other for a while. Or how bots don't pick up painkillers or throwables when they have the space for it. Or how they rarely heal you. Or how the witch can instantly take 99% of your damage while being almost unkillable. Or how jumpers seem bulletproof in mid-air. Or how when you are júst hit with Bile your gun disappears and you can't even spray some bullets around just in case. But if I were to tell you about everything that they failed to fix I'd be writing a book.
And then there's the kind of things that arn't needed for this to be a somewhat decent SP game, but things that I would just prefer to have in here. For instance giving a hold-your-fire command. Or a cover-me-command. And a way to identify the Singleshot and the Pump shotguns.
So to wrap it up. This game should not be sold as if it came with a singleplayer. This game is crummy enough as it is, but singleplayer is absolutely unbearable.