Type: Posts; User: Diex2005
It sounds like a cross between "The Labyrinth" and "Never Ending Story".
It actually Sounds like a lot of movies: Vertical Limit The Thing Twilight Zone: The Movie (I don't know if these help)
As for the 1st part, (rock climbing) I'd say "Cliff Hanger" with Sylverster Stallone. As for the Monster at the end, that's the end of "Big Trouble in Little China" with Kurt Russell.