Purgatory Academy Duology
In this over 400-page duology, you get not just the original stories, but a whole gallery, including the author's commentary, concept art, and early sketch pages.
Purgatory Academy is what happens when you have young adults who have met an early fate, the duty to decide whether they want to spend eternity in Heaven or Hell within four years.
If every story is an argument, then the first story asks the question, "Do we have the power to overcome systems beyond our control?" The second book poses the question, "Does it matter if we have free will?"
The concept is simple, but people are complex.