I own a copy of this Rock & Rule Marvel Super Special.
Between the fact that it's a 'photo-novel' (all of the panel artwork is basically 'still-frames' from the movie) -- and the all-too-brief "The Making of Rock & Rule" section in the back .. it's the closest thing this amazing animated feature has to an 'Art Of' book. Even the 2001 book The Nelvana Story devotes only a precious few pages to the film -- with fewer R&R images than seen in Marvel's adaptation!
.. not to mention the fact that Rock & Rule has never had a proper 'official' soundtrack album..!
There is a low-quality 'bootleg' soundtrack out there, though .. which, actually -- given its 1983 vintage -- is perhaps more 'period appropriate' than a squeaky-clean modern CD. I'd definitely spend money on the latter, however .. if only someone would license & release it!