I will agree that there should be some difficulty options, perhaps the current level as well as a hard and casual level above and below it. But it needs to not be a lazy +or- hp/dmg thing. Should take spawning frequency and numbers into account. I would be excited about more monsters, but not super excited about all soldiers being 3-star equivalents.

And I suspect casuals aren't often dying to one zero star mob. It's more likely getting swarmed by multiples.