The Marvel movies that never were - CNET

Then there's the legal issues. The history of Marvel is a tangle of legal rights for films, toys and other spin-offs being farmed out to other companies -- frequently followed by decades spent trying to claw them back.

The rights to Spider-Man were a tangled web for decades until Spidey finally became part of the Marvel cinematic universe in time for this year's "Civil War". Aquatic antihero Namor the Sub-Mariner is less fortunate, still drowning in rights issues and conspicuous by his absence on the big screen.

Probably the most notorious -- and hilarious -- example of a tussle over rights is the "Fantastic Four" flick filmed by legendary B-movie producer Roger Corman. He threw the film together on a shoestring so his rights wouldn't expire -- only for Marvel to take one look and throw money at the producers to bury the infamously shoddy affair:

Meanwhile some projects simply ran out of time. We're big fans of the "Daredevil" TV show on Netflix, but sadly, it put the kibosh on an intriguing 1970s-set proposal by "Narc" and "Smokin' Aces" director Joe Caahan when Fox held the rights to the hoed hero. The project fizzled when the rights reverted back to Marvel in 2012, but we can see what might have been in Caahan's sizzle reel of atmospheric clips from classic '70s crime and blaxploitation movies.

And of course, many of these projects were conceived before 1989's "Batman" proved how much of a box office sensation a superhero could be. They were also in the works long before CGI helped special effects catch up with the characters' special powers.