Heck Yeah!

Whenever another creature enters, you lose 1 life.

You don't lose the game for having 0 or less life. When you have 20 or more life, you lose the game. Whenever you lose life, you gain 2 life for each 1 life you lost. (Damage dealt to you causes you to lose life.)

Flying You can't lose the game and your opponents can't win the game.

Whenever you gain life, target opponent loses that much life.