I played the original Demon Souls game wayyy back when it released and got absolutely wrecked. We had rented it from a Blockbuster Video in my hometown (dating just how long ago this was lol) and returned it the next day after all 3 of us (myself and my cousins) got absolutely creamed in it.
These games are definitely no joke! What makes them unique though is that they follow up defeats with satisfying victories!!