各難易度のダメージ調整
INが被ダメージ、OUTが与ダメージ
Very Easy: In 2x, Out 1x
Easy: In 5x, Out 1x
Normal: In 10x, Out 1x
Hard: In 15x, Out 0.75x
Very Hard/Survival: In 20x, Out 0.5x