Add difficulty/challenge modes to dungeons

[Tint]

We want harder, but not static shatteringly hard. Please reread if you don't understand.

exactly, this game still lacks the middle-ground of difficulty. especially harder content for 4 people would be nice, because it's way easier to find and coordinate 4 people than 8. that alone will make savage content for 4 people easier than for 8 people and could fit the middle-ground.

i hope for deep dungeon, but my expectations are low :x