You can keep jumping to double jump in air, or to climb up walls in front of you.
Q: Slide Left
E: Slide Right
X: Slide Backwards
C: Clone or Substitution (You will need to slide in order to place it)
Controller:
Dpad: Slide (Left, Right, Down)
Y: Clone
Mobile controls: There are buttons on the bottom corners for all these commands. To create a clone, press the bottom right button, then slide with any of the other ones.