Be wary of the game’s alignment
The game is also off-center, and touching an object on Vals right on below him will kill him, depending on how close he gets, whilst the same object (eg spikes, korbat, etc) on his left, or above him, will not kill him. This is helpful throughout the entire game, but without knowing this level 15 is nearly impossible. – ddaniiel
Move and fire at the same time
You can move and fire in the same turn – click where you want to go, then, before you stop moving, press space. You’ll fire either in the direction before you moved (firing as soon as you start moving), or if you fire later, towards your new direction when you stop moving. Useful. – Aqua