Can I please do something cool now?
Difficulty: Many options available, challenging enemies requiring special tactics, platforming is standard third person fare. Difficulty is mostly from achieving high rank on levels more than enemies themselves. 7/15, multiple options and not being overly cheap at any point pull up what is a shallow difficulty curve
Lasting Appeal: DMC is a quest game, with little else to offer beyond a training mode, and a challenge mode. The game falls back on its combat and multiple difficulty settings really to generate any appeal long term. 7/15, fans will like it a while. Otherwise, it won't be long in your drive.
Overall: 6/15 decent combat with multiple options, provided players can stand it long enough to unlock enough moves.