It may not be intentional, but I just realized there's a similarity between "Stronger Monsters" and "Powers Combined." The bass is similar, and once the melody in Powers Combined kicks in, it's somewhat similar to Stronger Monsters.
I don't think it's close enough to call it a leitmotif. But I'm filing it away just in case. And it is interesting to note that combining their powers does make them stronger. (Maybe that's really the whole point of DR???)

















