How can I make sliding and wallrunning?

As said in the title I would like to know how to do these things!

sliding

how can I make it so if you slide downwards you go faster?
And well Im assuming this wont be very hard but I need to make it so when you press a button on your keyboard you start sliding.

Wallrunning

Pretty straight forward. You run, on a wall.

If you need any more details feel free to ask!