Please see photos for what is included and condition. I do believe that the PAL version of this game didn't have a cellophane seal only the stickers seal that can be seen in the photos.
The box does have some slight denting / bellowing to the one side as can be seen in the photos. I do have other yu gi oh boxes that were opened and the cards inside some of them did have curvature to them so it is possible that the cards inside this box may have curvature too.