You’re Derpy Hooves, mail mare. Spike’s ill, so Twilight Sparkle has asked you to fly her letters to Princess Celestia. But Gilda is harassing you! Fly around and press button two to drop an anvil on her. It’ll make her much more angry, which is probably not all that good of a plan, to be honest. Avoid getting hit by Gilda – she’ll steal one of Twilight Sparkle’s letters. If you lose all three, you have to return to Ponyville.

This is a very basic game with no real ending – it just gets harder and harder until you lose all you lives or it loops around and goes back to the starting difficulty.

http://www.smspower.org/forums/viewtopic.php?t=13665