First of all this would be broken with Final Fortune, which does not target. Secondly, is your intention also to prevent you from losing the game from loss of life? Also, if your intention is to prevent mana burn, not having your pool empty is way too powerful a way.
Here's some modifications:
Alternate Universe

Enchantment
If you would win the game, instead you lose the game. If you would lose the game, instead you win the game unless your life total is less than 1. You can't play instant or sorcery spells and you don't take mana burn.
Perhaps this is missing your original intention, though - let me know.