Add a tiny tutorial level before the main one

[Siôn le Roux]

A lot of players first attempt doesn't result in much because they either tap instead of holding down to charge the jump, or immediately hit some terrain and get stuck. A tiny 640x480 map with one hill and/or one lake to jump over and a text in the sky to say "HOLD DOWN to jump far" would be enough to teach this and the rest of the game would be less frustrating.