7. Batman: Arkham Asylum
I feel kinda bad putting my beloved Batman Arkham series on this list, but there's no getting around the fact that fighting a roided-up Joker who'd taken far too much Titan was just a bit unnecessary and was a bit of a blemish on what was nearly a perfect title. Thankfully Arkham City's ending was much more satisfying and intriguing, so we can forgive it somewhat. It all makes sense in terms of continuity with the next game as well, but the boss fight and subsequent defeat of the Joker and his scheme to take over Arkham Asylum using roided-up supersoldiers weren't as spectacular as the rest of the game was.
Original Ending The Joker, after being mostly foiled by Batman, injects himself with the serum Titan that Bane uses to go all huge and stuff. The subsequent boss fight takes place atop Arkham Asylum with the Gotham News watching on. Batman has also been infected by Titan, but uses his new antidote to cure himself and knock out the Joker with a massive smack to the face filled with explosive gel. The Joker, defeated, then is seen taken away with the effects of the Titan wearing off. A mysterious hand then surfaces from the river on top of a Titan crate as Batman goes once again off into the night.
Alternate Ending In a game where the boss fights are generally extremely well done, having to a fight a massive version of the Joker was just silly. Fair enough Joker could have had his army of Titan soldiers fighting Batman for a bit, but the main fight should have been a battle against Joker's deranged games, culminating in a showdown with a normal Joker instead. This idea was sort of used in Arkham Origins where the Joker converted a hotel into a funhouse of sorts filled with deadly traps. Let's face it though the Joker's biggest strength is his ability to get in Batman's head. He knows what makes Batman tick, and since Arkham Asylum takes place in a Batman continuity where the two know each other already very well, I'm sure he could've came up with a better plot than this one. More emphasis should have also been placed on Arkham City - a glimpse of Hugo Strange or the plans for Arkham City (which are in the game, but hidden behind a secret wall), would have been a great hook into the next game.
Alternate Alternate Ending After knocking Bane into a river with the Batmobile, Batman summons the Batwing to knock the Joker off the tower into the river as well. It's a hobby.