Interesting premise, the idea of what a "friend/sidekick" character could do to break out of his role, but they don't really do anything with it to make it stand out. The story ended up with the protagonist taking over the role of the hero, and taking all the heroines that would have been the hero's. I am not saying that isn't a viable path, but it's not done well. The author doesn't do it in a way to make the story interesting, like the ways to put the odds in the favour of the protagonist through game mechanics, or flag raising with heroines. If youcompare Magical Explorer with something similar, "Kami Nomi zo Shiru Sekai (The World God Only Knows)" does it better.

Art is decent, but that's pretty standard with novels.

Characters are basically exactly as you'd expect, cliched cutouts of characters from eroge. Sheltered princess, strict but kind maid, etc. Not going to complain too much about it, but it does get tiring if you already watched/read a decent amount of stuff.

I'd put this story in the category of "stuff you'd read to kill time". You're not really missing much if you skip out on this.