I'm not 100% sure if this counts as lost media, as the media seems to also encompass unfinished/unreleased/cancelled media. Anyway, after the game Spider-Man: Web of Shadows was released in 2008, there was a sequel that was worked on called Spider-Man: Classic. According to B.D. Fulton, the guy who revealed the game's existence, the game would've "[revisited] classic Spider-Man villainy in short-story fashion, like a best-of anthology of boss fights, told in panel-by-panel faithfulness to the original comic." The thing is, the only information about this game comes from Fulton, and outside of what he revealed, nothing about it exists in the public eye. I did email Fulton, asking if he'd answer some questions. If he answers, I'll mention it. Until then, does anyone have any other info about it?
Also, here's what's been revealed about the game so far: