Dream Dice RPG

I thought it would be a novel idea to give players four dice (a d4, d6, d8, and d20) to fight random monsters in an RPG. Originally you wouldn't know which dice you were rolling, but a bit of play testing revealed that to be total chaos.  Then I came up with the idea to make monsters resistant to certain numbers. For instance, ogres can't be hurt by 10 or less, while bats can't be hurt by 5 or more.

Then I realized I had made the basis of every RPG system. At first you don't know what abilities are effective in certain situations, but as you gain more experience you can make optimal decisions based on game logic. So much for being original!