Strong Female Protagonist, Book Two: the hard philosophical questions of superheroism and compassion

It's been nearly four years since the first crowdfunded collection of Brennan Lee Mulligan and Molly Ostertag's webcomic Strong Female Protagonist was published; the second volume, published this week, traces not just the evolution of its protagonist, the superhero Alison "Mega Girl" Green, but of its creators, who have found new and amazing depths to plumb and heights to soar to.