Grab the stars and make it to the exit. Sounds easy enough! All you have to do - and this is where it gets tricky - is make sure you never end up standing entirely in the dark! Grab fireflies to light your path, and try to make it to the checkpoints and the exits on time, before their light fades away.
Arrow keys = Run and jump
Mouse = Click anywhere in the level to release a firefly once you've caught one or more