Walk in the shadows (invis, u make it so that its not to op)
Shadow revenge ( chance to make a black hole at death)
Shadow retreat[ability] (fall into the ground for 4-6 seconds)
Shadow walking[ulti] (walk through walls but u cannot shoot while doing this, so u lose ur gun while inside the wall, but when u get out u get it again)

I posted this in many different places, and the best result gets used in my coming server

No, its impossible. You can't detect if its floor or ceiling and only allow player to go through walls.

you can with out falling you just dont want to go under the map useing the varable est_noclip server_var(userid)