Battlefield: Bad Company 2.
The last level was the most terribly designed arbitrary and anticlimactic piece of crap I've ever seen. Allow me to explain.
The level is a series of 2 or 3 tiny, completely linear corridors each with about 3 guys in them. The game arbitrarily forces certain weapons into your hand to deal with each one in the way it wants you to. First corridor? You must use this special assault rifle. Second one? Here, have this automatic shotgun. It's incredibly repetitive, incredibly linear and very short, not to mention boring.
And then, you get to the cockpit, and find that nobody's there. The main villain (Mr. stereotypical Russian evil guy, see playthrough of Duty Calls) gloats at you from a TV screen as his EVIL CONTRIVED SUPERWEAPON OF DEATH prepares to fire. But evidently, it does nto enter his mind that you can just walk over to his location! What a bumbling ninny!
Anyway, when you get to his supposedly foolproof office containing the evil superweapon and break the glass of a window to make a way in, he's like "OMG! How could this happen!? I never thought somebody would break the glass to get in! Curses!" The game then forces a pistol into your hand for absolutely no reason whatsoever and makes you shoot the superweapon with it until it asplodes. Any particular reason I couldn't use the Assault Rifle you thrust into my face about 10 minutes earlier? Why, DRAMA, of course!
The plane then begins to crash and burn, and you all jump out and activate your trusty parachutes. However, Mr. EvilRussianGuy has also jumped out (evidently, his mastermind-level brain forgetting to grab a parachute of his own), and you have to shoot him with the same pistol as before... before a stupid and completely arbitrary (noticing a theme here?) time limit runs out, or you lose and have to try again. Lemme clarify this for you: The big bad guy of the series, the guy you have to chase throughout the entire campaign, the guy who carries the threat of wiping out the USA, poses no threat at all other than a stupid time limit, and takes a mere few pistol shots to kill. You know the trope Anticlimax Boss? This guy is the lord grand master of it.
Oh, and after the ending cinematic throws you with a silly plot twist, the end credits don't even have any music. It's just the ambient sounds of the main menu. I made a vow long ago to sit through the end credits of every game I take the time and effort to complete, but doing this here was a bloody ordeal.
It's a shame, really. The rest of the campaign was decent, and the multiplayer is excellent. I'm hoping BF3 will have a better climax.