Original NESs didn't expect inputs of left+right or up+down, because of the way the controller was designed. For most games, this is harmless, but in some games it has quite detrimental effects (it appears to crash or reset BurgerTime). There should probably be some option to toggle allowing these inputs, as they sometimes have some uses, or it may be interesting to see their effects, but for games like BurgerTime it's difficult to play on keyboard without breaking the game.
Original NESs didn't expect inputs of left+right or up+down, because of the way the controller was designed. For most games, this is harmless, but in some games it has quite detrimental effects (it appears to crash or reset BurgerTime). There should probably be some option to toggle allowing these inputs, as they sometimes have some uses, or it may be interesting to see their effects, but for games like BurgerTime it's difficult to play on keyboard without breaking the game.