Okay, here's one: Indiana Jones and the Last Crusade: The Action Game. Not the SCUMM engine adventure game made by LucasArts, no I'm talking about the godawful action platformer that Tiertex smeared across every console and home computer of the early 90's like shit across the handicap stall in the men's room of a Ruby Tuesday. I knew it as the particularly heinous MS-DOS port but they put it on everything from the Commodore 64 to the Game Boy.
The controls are bad, the mechanics don't make sense, the level design is bullshit, the enemy design and placement is unfair, the graphics are mediocre, the audio is bad to horrible depending on the port...it has no redeeming qualities.
I hope it's obscure because lord it deserves to be forgotten. How do you take a white hot license like Indiana Jones and fuck it up so comprehensively?