1. Zelda II: The Adventure of Link
Everyone loved The Legend of Zelda's then unique top-down, action-adventure style, which defined the genre for years to come. Naturally, Nintendo wanted the follow-up to be something completely unrecognizable. If internet acronyms existed back in 1987, there would have been a lot of WTFing going on.
How It's Different From The Original: I don't think anyone expected the sequel to The Legend of Zelda to be a side-scroller RPG with magic spells, extra lives and a world map. Not to mention a final boss that is literally your shadow. And just in case people weren't confused enough, it was the only game in the series to proactively avoid name recognition by eliminating "The Legend of Zelda" from its title. Also, the graphics were a lot uglier in a number of instances. Such as the instance of "the whole thing."
Fact: An NPC's first line of dialogue is "I am Error." This is a mistranslation of the Japanese word for "Jerry, don't forget to translate this."
Also: This is THE Adventure of Link? I'm pretty sure he had a bunch of adventures. Like, including the one right before this one and about a dozen after.
2. Super Mario Bros. 2
Okay you just made the single best-selling game of all-time, launched what would be the most successful console ever, and made an overweight plumber one of the most beloved and recognized characters in the world. You can finally relax a little, right? No need to strain yourself too much with the sequel. Let's just stick Mario in someone else's game! Not like anyone would have bought "Doki Doki Panic" anyhow.
How It's Different From the Original: Suddenly you're not limited to playing as Mario or Luigi you can play as Princess Peach or Toad as well, and everyone has different abilities and a life meter now. Also, jumping on enemies no longer does anything you have to chuck beets at them. And Koopas? Long gone. Now you have to fight masked midgets and blowjob dinosaurs. And King Koopa? Psh, as if. Now you have to fight a burping frog. Much better. Oh, and it's all a psychedelic mushroom-induced dream anyway.
What?: Yeah, blowjob dinosaur. Excuse me, drag queen blowjob dinosaur.
Also: The Japanese version of Super Mario Bros. 2 was eventually released in America as The Lost Levels, where you found out everyone was dead. But at least they got to go to Best Friend Heaven in the end.
3. Toejam & Earl: Panic on Funkotron
The most 90's game ever Toejam & Earl was a great, unique game. You played as a pair of all-that-and-a-bag-of-chips aliens stuck on Earth, going to randomly generated levels to piece together a spaceship while dealing with weird Earthlings, interdimensional elevators, and mysterious presents along the way. At the end of the game, the duo returned to their planet of Funkotron (the perpetually early 90's planet in the Fresh galaxy) and thus this weird game was born, taking out all of the fun stuff from the original and replacing it with something else.
How It's Different From the Original: You're still playing as Toejam & Earl but now you're on the overly purple planet of Funkotron, the gameplay has changed to side-scrolling, and the word "funk" is tossed around nearly 20 times per level. Did I mention things are SUPER FUNKY now?! Because they certainly are. "Funkapotamus," "Funk Dimension," "Funk Scan," etc. You spend the whole game throwing jar after jar at the wacky Earthlings roaming the side-scrolly planet like a tedious game of hide-and-go-funk, instead of the laid back exploration of the first.
Wait : Yes, the first one was supposed to be Earth, even though you were on floating chunks of land hovering in outer space.
Also: No more robbing jet-pack Santa Claus. Bummer.
4. Castlevania II: Simon's Quest
Castlevania started as an incredibly lazily-titled platformer (hint: it took place in a castle in Transylvania.), starring a pixel-y dude with a whip who hated candles almost as much as he hated vampires. Remember when vampires were bad guys, instead of tween heartthrobs? Anyways, Simon Belmont, the aforementioned S&M vamp-hater, was bound to return. Except things would be a lot more Metroid-y the second time around.
How It's Different From the Original: This is the game where Castlevania laid the groundwork to its eventual greatness. Instead of going through level after level of a castle, there was just a large area to explore at your own pace. Like Metroid before it, you can only enter certain areas until you gain certain abilities or items, but it made for a lot more interesting gameplay. Suddenly you could go to towns (awesome) and listen to poor translations that will confuse the hell out of you (not awesome).
How Bad Were the Translations?: "Hit Deborah Cliff with your head to make a hole." This was the hint they gave you to go to a certain wall, kneel down while equipped with a red crystal, and wait for a tornado to take you to a new location. Which is just common sense, really.
Also: And just in case nerds weren't depressed enough by the general impossibility of figuring out what you were supposed to do in the game, if you didn't finish it fast enough, Simon died at the end. Sucks to be you, kid in 1988.
5. Pac-Man 2: The New Adventures
Everyone knows about Pac-Man the story of a simple yellow circle running around a graveyard being chased by the restless ghosts of the men he murdered. It was an instant classic and there were follow-ups, such as Ms. Pac-Man, which made the crazy change of adding a bow and make-up to the main character. But did you ever wonder about the world Pac-Man lived in when he wasn't doing cemetery laps? Or what he would look like with arms and legs? Apparently someone did.
How It's Different From the Original: Well, for starters, you don't even play as Pac-Man. Pac-Man's there, but you're just you. You can point Pac-Man in different directions or shoot him in the face with a slingshot. Also, you'll come to meet the whole Pac-Family! There's Ms. Pac-Man, Pac Jr. (their "radical rock 'n roller" son) and Pac-Baby (whose parents must really, really hate him based on the name alone). The game ends up being a giant puzzle quest, filled with weird humor, cat attacks, and Pac-Creatures of all varieties. And it all ends with a fight with a giant Gum Monster. So if you loved the original Pac-Man, you'll agree this is also a videogame!
Why Is It a Pac-Man Game?: I have no idea. To be fair, this is barely even a game.
Also: Man, Pac-Man really had an overeating problem, didn't he? Even being stalked by ghosts wouldn't slow him down from chowing down on those pellets.
6. Star Fox Adventures
Fox McCloud used to spend his days flying around the galaxy, saving his unhelpful teammates from repeatedly dying and trying to protect the galaxy from a disembodied monkey head. He never got out of his Arwing ship because why would he? He shot lasers and mini-nukes out of that thing. Wings would magically reappear just by flying past some icon. Hell, it could fly without any wings! It was a pretty sweet space-jet, perfect for killing giant robots and annoying meteors alike. And evil dinosaurs? Oh yeah, it was pretty much the perfect tool for killing evil dinosaurs. I bet if there were a planet full of evil dinosaurs, Fox would just fly by 'em and drop some laser shots on their ass. The whole thing would be over before Peppy could recommend some type of sideways spinning move, right?
How It's Different From the Original: Wrong. Fox left the Arwing behind to run around the planet on foot. Well, at least he brought some type of laser pistol with him, right? Wrong. He now uses a magic stick! The game looks, sounds, feels, and smells a whole lot like Ocarina of Time, probably because it was originally an Ocarina of Time clone totally unrelated to Star Fox. But Nintendo realized that Star Fox was a valuable franchise, and "random dinosaur Zelda knock-off" was not. You do the math. Shockingly, Slippy isn't around to be constantly in danger and annoy the hell out of you. Don't worry though, because the developers honored his memory by giving you a pet baby dinosaur to constantly annoy you.
Remember : how heavy the Rumble Pak was? That thing, like, doubled the weight of your controller. Still worth it though.
Also: Okay, you do get to use the Arwing at the end. And Falco shows up for about two seconds and still manages to be a complete dick about everything.