2. Super Mario Bros. 2
Though the Japanese got the "proper" version of Super Mario Bros. 2 in 1986, the Western world wasn't so lucky, as the original version was deemed to be difficult - somewhat ironic given that Japanese versions of games are typically easier than Western versions now - and we instead received an altered version. Well, altered would be a kind word; what we got was a re-skinned version of another game called Yume Kj: Doki Doki Panic, and given how the game was already conceived as a tribute to Mario, not much had to be changed other than some models. The game was a major success regardless - given that most people were unaware that it was a rip-off - and though it continues to be regarded as a great game, at least in the world of the Internet we all know the truth now, and it doubtless colours the reputation of the game in retrospect. Though enjoyable enough to play, there's always that thought ticking in the back of our minds that we're not playing the proper game, and this was just lazily cobbled together.