He was definitely different. There haven't been a lot of attempts to stage his stuff. Orson Welles did a movie version of The Trial, which you'd think might've had a chance (hey, it's Orson Welles, and while he was still fairly young and extremely ambitious!) but it flopped. The Metamorphosis staging is weird (of course). They don't use a costume for Gregor but he does go around on all fours.
Amerika probably could be produced; it's not as surreal. And there's also In the Penal Colony, which might be possibly now, given CGI effects, but it would be brutal and probably get an R rating for extremely graphic violence.
Ah, Tim Roth played Gregor:
http://www.imdb.com/title/tt0093530/
And here's the Trial, with Anthony Perkins:
http://www.imdb.com/title/tt0057427/
Here's a link to all of Kafka's stuff, either made for TV or film:
http://www.imdb.com/name/nm0434525/
I had no idea In the Penal Colony actually was produced, and also The Castle (a very odd book, I wonder how they made it into anything that could possibly be staged) and Josephine and the Mouse Folk. Wacky.