You need to decide one way or the other... I think everyone agrees on that. From the looks of it, I would go with a challenge. Awesome graphics only add to the fun of a challenge, and make people want to play it more. Personally, I have never even played an environmental level, as I have no interest in them. To me, they are fairly... boring... I like action more than just viewing, but that's just my personality, no offense meant to environmental levels. I do, however, appreciate a challenge with amazing graphics, because then, I don't care as much when I die.