I enjoyed it. One of the major enlightenments that all the critics fail to mention is that Marks miniature world has one single character not based on a real person in his life. I clued in pretty early on that the blue witch of Belgium was in fact a metaphor for his addiction to presumably opiate pain meds.
Defeating her in his fantasy story, is direct parallel to him realizing that his abuse of the pain meds are likely whats causing his PTSD and flashbacks to be so severe. This is confirmed moments later when you see him rinsing his pills down the sink.
This part of the story alone i found very powerfull and moving.