Jet Jumper

There are a few levels in the game where in the very beginning of the level there's a life extra. Start the level collect the life extra press escape, suspend game. Now in the menu select the user you were playing with, then "Resume game" and you're on the same level as you were a second ago, but the life extra is still there as well as the life you've just collected. Repeat this procedure several times to get as much lives as you like. (Now I have 30 for example)

Unless you hit something or melt to die you have to fall of the edge, theres a way around this. When you fall of the edge, before you die, press Escape, then "Suspend game". In the menu select your user and "Resume Game". You're in the beginning of the level you've just fallen off but you haven't lost a single life!