Muramasa's core question is simple - can killing ever be justified? - but in a world of often cut-and-dry morality, where it's clear who should live and who should die, the suspension of disbelief can be easily broken. The world is very interesting, the fights are great, and when humor is present and intentional, it's very amusing. Unfortunately, the absurdity and contrivances at the core of the story do render its explorations somewhat juvenile and difficult to take seriously. I would recommend starting with the Kanae route as the Ichigo route - though you'll have to read both to see the true route - is the most 'stupid.' That might be the point, though.