Please note this is by no means a definitive list, so feel free to include your own disappointments in the comments. Also note that "follow-up" usually means "direct sequel," but not always. And last but not least, just because you liked a game doesn't mean it didn't disappoint many other people. Sorry, just trying to cut down a bit on the inevitable gnashing of teeth and beating of breasts.
9) Marvel Ultimate Alliance 2
Marvel Ultimate Alliance did what few Marvel-themed games could before: take the scope of the Marvel Universe and put it into an exciting RPG. It was a huge hit which DC still hasn't topped. And as hyped as the 2009 sequel was, it delivered... well, much of the same, but not as well put-together. Playing as different characters in the sequel didn't make much of a difference after you discovered that all their superpowers were virtually the same, just done with a character-specific bent. Everyone had the same attacks, worth the same amount of damage. The RPG fun was sucked out of it, making it just another beat-em-up, just with better skins.
8) Devil May Cry 2
The first Devil May Cry was the perfect storm of videogame successes, where beautifully rendered characters and environments propelled a great story with a great protagonist and really awesome monster-killing gameplay. For a PS2 game, it looked like fine art. Then the sequel came around in '03. All the beautiful backgrounds? Eh, not so much. The gameplay was drained of its strategy and became, annoyingly, easier. And the awesome character of Dante became uncharacteristically dull. In the race to improve on the first game, Capcom took away its teeth, a deficit the series tried in vain to correct with future releases. Oh, and it came with a second disc where you could play the same game over with a different character, making this a disappointing sequel and a disappointing three-quel in one package.
7) Star Wars: The Force Unleashed II
Continuing LucasArts' unwritten rule that Boba Fett must be incorporated into every project going forward, as penance for killing him in Return of the Jedi, guess who pops up in last year's Force Unleashed II. But that's not the only thing that made this sequel a miss. Repetitive gameplay, repetitive enemies, repetitive stages, and relatively short time to completion left audiences less than impressed. The game retread a lot of the same ground as the original without taking the same risks. And in the end? Eh.
6) Deus Ex: Invisible War
It's funny, because as I write this, probably 20% of the people I follow on Twitter are playing the third installment of this FPS and tweeting about it. Flashback eight years and you heard people complaining about the first sequel, Invisible War. Perfectly fine if you hadn't played the original, but once you'd tasted that sweet fruit, virtually anything was going to be a let down. Drop the RPG elements, the functionality, and reduce the game's length, and you've got yourself a disappointment. Luckily, from what I heard, the new one, Human Revolution, is worth your time.
5) Perfect Dark Zero
The original Perfect Dark was really a spiritual sequel to Goldeneye, and the sequel to Perfect Dark is an all-around failure -- a failure that absolutely stomped a promising franchise to death. Despite five years between games, Zero made serious missteps. The protagonist, Joanna Dark, received an unneeded redesign, making her much more cartoonish than necessary, and the shooting mechanics and level design were atrocious -- gamemakers even had to include arrows on the floor telling you where to go. While possibly okay as a stand-alone game, it didn't do the original (or the follow-up novels) any favors.
4) Tomorrow Never Dies
What made the N64's Goldeneye awesome? First person shooting and a multiplayer that still holds up as a weekend's worth of dorm room fun. What didn't Tomorrow Never Dies have? First person shooting and multiplayer. Go home, son.
3) Super Mario Bros. 2
Let's get one thing clear: this game is awesome. It's the fruit salad to Super Mario Bros.' apple slices. But the thing is, it's not a Mario Bros. game. It's Yume Kōjō: Doki Doki Panic, a Japanese game that had the main character sprites replaced with the Mario cast, just to get product on the shelves back in '88. While it's fun, and it requires its own skill set to master, it carries over virtually none of the elements from the first hit game. Stomping bad guys is out. The familiar platforming is out. Familiar villains are out. Radishes are in. For too many kids in the '80s, this wasn't the Mario they were comfortable with.
2) Kingdom Hearts: Chain of Memories
Disney RPG. That's all you have to say to sell the first Kingdom Hearts (hell, that's what sucked me in). It combined real-time action with the epic scope of Final Fantasy and familiar lands and characters. And Kingdom Hearts II just expanded on that. But in between, in 2004, there was Chain of Memories. A fighting style based on cards, plus a skewed Final Fantasy:Disney character ratio made this a "hey, it'll tide you over before KH2 next year" game, rather than a champion sequel to a monster hit.
1) Zelda 2: The Adventure of Link
The first Zelda game was a watershed in video games. Easy-to-use controls and gameplay, as well as a dynamic story, took the fun parts from tabletop fantasy RPGs and made them accessible to the typical NES customer. The 1987 sequel took away the familiar characters, the top down POV, and the open-to-explore environment and replaced it with a difficult side-scroller where a player could easily be tripped up. Gamers who liked a world with open plains and explorable dungeons now had to face jumping, which made the game more of a Castlevania clone. The games have evolved now to place where those platformer elements are better accepted, but you have to remember that the next two games after Zelda 2 went back to the top-down gameplay.
Tags: Deus Ex, Devil May Cry, James Bond, Kingdom Hearts, Legend of Zelda, Marvel, Super Mario, The Force Unleashed