I made some covers. They are not that great, but..

a couple of things i notice straight away is Batman the synopsis needs aligned properly, and the legals and logo need nudged up away from the bottom edge.

spider man i like the front but back layout still needs a lot of work.

your ideas are great there just a little rough round the edges if you know wot i mean

A couple of things I'd reco for the Batman cover - On the front I'd go with larger TT and names, batman's right hand side looks really harsh at the mo try some feathering and/or darken the edge a bit. On the back - what db suggests and make the review bigger I think I'd also increase the size of the credits as well.