Gather crystals as you escape the ever-approaching Wall of Doom!
Mouse + LMB. Click and hold to hook yourself onto a wall, release to fall back down. It's really that simple!
If you want an extra challenge, try increasing the Game Speed, Wall Speed, Obstacle Count or Gravity at the Terminal at the top of the hub! You can only do that once you buy the Padlock Key from the Barkeep, though.