W or Spacebar - Jump A or Left arrow - Move left D or Right arrow - Move right Hold Jump while under yellow tiles of Magnetite to hold onto it, allowing you to run along the roof and jump up and off. Light green orbs of Gravatite allow you to manipulate your gravity while within them, slowing your falls and allowing for double jumps. Falling from the upper levels will send you down into the lower ones.
@griffpatch for the tutorial on how to make a platformer.