portcullis Trap.
Basically the floor traps open/close the portcullis doors ahead to continue through the level the end door must be open and a path to get there but one false step and all doors close.

Maze of Misery
I tried a few things and it just wasn't working out so I came up with this idea for a maze.

Short in game movie
http://www.youtube.com/watch?v=SQeGQAn92p0
I liked the concept except for a few things, the major one was I could see the edge of the maze (you enter a Maze you should get disorientated).
So with the next build of the maze there will be no edges - the player will be ported to the center of the maze and with some luck no matter how far you walk in one direction you will never see the edge of the maze.