Why is Demon's Souls seen as being a 'hard' game?

[Slimebeast]

Xen said:

@slimebeast: If so, then this gen is really pathetic for difficulty. Wake me up when we're in the 16-bit days again.

Maybe it's pathetic but it's true. Maybe some arcade games like Icaruga are harder but from the retail games DS is the hardest.