I don't think WVM is a bad game... but what in the hell about this game is ANYTHING like WVM?
The setup for the Harem is way different, this game has a MUCH smaller pool of LI's. The story and setting are completely different, and they look completely different graphically, especially the models. The pacing isn't the same, and like... must I keep going, I think I've made my point.
I will point out on more thing though, the main love interest in Between Two Worlds, isn't nearly as enthusiastic and readily willing to share her man, especially romantically. While in the other game it's like he's with the queen of all cuckqueans.
So please explain to me how this game is anything like that game.
It's really not much like Eternum either, except for the isekai similarities. Although they're both isekais, the settings and storylines are much different between these two as well, and again completely different graphical styles too.
Between two worlds isn't really like any other game I've personally played on here, and it certainly isn't a mix of the two games you've mentioned. I agree that this game is amazing though, and it definitely deserves the praise it gets.