Pure fan service wank, but still well crafted enough to read. Everyone is fairly likeable, and have their own motives. The main mechanic of the story is interesting, and they explore the possibilities of it rather than just getting plot mandated upgrades when ever they meet stronger enemies. MC is a doormat, but it actually makes sense within this context and he still comes of as charismatic in his own way. He is at least, not as simpering and servile as a lot of protagonist in this situation. He has clear goals and aspirations, and is working toward them.
While we have the regular harem antics, (there is more than one female character, so it only follows) there's really only two characters who have openly expressed feeling for the mc as I'm writing this, the rest are just "friendly" (you'll see). As of ch.29 we're getting a little intrigue as well, so if you make it that far, you may not regret it.