Absolutely one of the most polished adult VNs I've ever seen. I'm thrilled you guys are getting the time/resources to make this something special. The cinematography is oddly good and the detail of the 3d scenes bring a level of authenticity to the writing that most games don't have the directing skill or the development resources to do. Many of the choices you've made during development (quality > quantity sex scenes, emphasis on line-by-line storytelling and animation, and SOUND DESIGN most of all) make this game stand out amongst its peers. Seriously - keep licensing good music. It's unbelievable how big of a difference it makes for the player experience.
All these things in mind - have you considered getting the game partially voiced? RAVAGER is a good example of a game that's gotten a LOT of benefit from voicework and I think Eternum can in the same way. There's probably ways to do it where some scenes are voiced/some aren't - as voicing the whole script is obviously unreasonable - but it might be a good stretch goal down the line to enhance the "cinema" feel of the game. There are plenty of places online with people willing to do voicework - /r/gonewildaudio is a good starting point to find actors who can do regular and sexual VAing.
Thanks for giving us such an awesome game, people over at Caribdis! And, as an amateur Renpy game maker - thanks for setting a high standard that the rest of us can look up to and learn from!