The ending to Shadow of the Colossus.
I can tolerate being used. I even suspected that, but I spent hours galloping across vast expanses, climbing ledges, and slaying impossibly large beasts, and it all ends with me being randomly swallowed by a random glowing pool that randomly turns me into an infant? Who would design that sword and the castle to do that? What kind of twisted magicians would design magics that do that for no reason? What kind of lazy, drunken script writer lets the game end that thoroughly random and disappointing way? I give that effort, and I tolerate big-but-boring landscapes with repetative gameplay and useless game-mechanics that I never have a reason to use (why can I duck and stand on my horse?), and you have the gall to turn me, the mighty colossus-slaying hero, into a baby?
If there is no alternate ending to unlock, I am going to be even more annoyed.
There IS NO alternative ending, though you can outrun the vacuum, only to be blocked by an invisible wall at the bottom of the stairs before the the slab where the girl is. Do you want to know the crazy part though?
the girl disappears when the vacuum appears. She must have been an illusion all along.
Also, sorry for the double post.
Not sure if she was an illusion, since she carries what's-his-name up to the top of the temple, to that garden thing.
Which, by the way, you can climb up to early if you keep replaying the game with the same save, eating the tails from the blue-tailed lizards to permentantly increase your strength (and of course, beating the Colossi increases it as well), until you're strong enough to climb the moss on the back-right outside wall of the temple (i think it's right, don't think it's left, i haven't played in a while, but i know it's outside in the back). You can't climb back out, so you gotta revert to save etc. but still, man this game has a fair few hidden details you never find if you just ride from A-B to the Colossi.