Follow the dwindling sphere with the mouse. straying off makes you lose energy.
Princess Peach is on the other side of the desert and she needs some fresh water. Have Mario bring it to her before time runs out!
David Bowie will not help you in this labyrinth. Instead, similar to QBert, you need to fill the entire grid without trapping yourself.
Make some snowballs and whack innocent passers-by in humbug fashion.
Kill the droids by deflecting lasers into them