The right formula, just nothing is done with it
My first impressions of Killzone 2 were great because of it's detailed graphics and powerful shooting but as I delved further into it I realized while they had the formula for a brilliant fps they did nothing interesting with that formula more so than the first few levels. The campaign drags on through one gritty shootout to the next with little to keep it fresh, they do somethings to keep it varied but they stay extremely safe in ways of doing this. You get new weapons, none of which are really new except the overpowered electricity gun you get at one point. Then the mandatory vehicle sections which are just really shooting things from a different perspective, except maybe the tank section which was confusing and restrained. The level design could of made up for this but for a long time it's just going through tedious grey corridors, though the train level was pretty cool.
The story, the characters they don't do anything for me. They get credit for trying to make you sympathise with the characters but they don't pull it off because the dialogue is all so forgettable, they don't really say anything that characterises them particuarly well or makes them seem sympathetic or intelligent or funny. Then there's Rico, what the hell? The guy who you're with for most of the campaign is plainly put, an asshole and the game seems to realise that as well.
The multiplayer then, I suck at multiplayer so a lot of the things I want to write I won't because it could just me being a pussy. Other than that the class system while shamelessly like Team Fortress makes the multiplayer nice and varied and the idea of having the game objectives switch of the fly and not having to spend as much time in the lobby is obviously a good thing. Still, some games where players are mostly pushed inside and often near a spawn point it becomes a horrible game grenade and rocket dodgleball. And the turrets shouldn't be able to get headshots.
Oh, but the graphics are awesoooooooome!