I went into this graphic novel fresh. My son is a fan of the series and I bought him the graphic novel because he likes Adventure Time (who doesn't?). I haven't seen the web series yet, but it looked interesting enough so I gave it a shot.
First off, I really liked the presentation. The designer did a really great job putting together a retro-ish style. Honestly that was my favorite part of the book. The story was all over the place. Hey, the book is for kids so it's okay to be random? Question and statement. It had a sort of ADD writing style that I noticed in Adventure Time (maybe copying or tying too hard). Not saying that I'd rather a heavy pulp sci-fi novel, because that wasn't what I was expecting. The story jumps around a lot in the beginning, but got better with the last issue (Note the cupcakes.)
Art wise it is what I was expecting. The characters aren't very detailed, but they are well animated and pop from the page. I hate to keep making references to Adventure Time, but the designs are obviously similar. The art really drove he story, even if the "stock action poses" were used a little too often for my liking. The inclusion of a cover gallery was welcomed, mostly because of how many variants there were!
I'd say this was a 3.5 out of 5. My son would likely disagree and rate it higher, but he can write his own dang review. =)
Fair warning to parents out there, the book is a bit violent and has mild sexual situations/references. The age rating should be 13+, so watch out if you're expecting something for younger audiences.