Going by the screenshots, I expected this game to be a lot sillier than it actually is, and I find myself quite engaged in the plot, even if it borrows heavily from anime and can be extremely over the top, with one of the most Gary-Stu protagonists since Kirito from SAO. The fact that this plot still engages me speaks for the world and characters you have created, so kudos for that.
However, while I get that we control a character who isn't us, and we have to adapt to that fact, it felt punishing to also adapt to his fetishes without any consideration for our own. Yes, we get to choose whether or not we want to bang the sister and/or mother, but we don't get to choose who is our favorite demon/angel, as the protagonist simply defaults to Lilith. Then, despite having picked the petite, small-breasted demoness as his absolute favorite, the game decides that tall and big-breasted is definitely better. I happen to much prefer petite and reasonably-breasted, so when Lilith grew tall and inflated her breasts as her special show for the protagonist, I was extremely disappointed. Isn't the whole point of having a big harem of many girls with differing bodies and personalities to cover a wide range of fetishes and tastes? There are plenty of taller girls with larger breasts, so turning the one petite girl with smaller tits into a tall MILF with big boobs really doesn't feel like the right choice, and when the protagonist basically reacts with a "hell yeah", I have never felt less immersed as a result.
Aside from that, nice VN so far, even if the grammar does need a beta reader who is fluent in English, and the choice to use Unity seems to be detrimental to the performance. Loading a game in a VN shouldn't take 30+ seconds, and rolling back or advancing dialogue shouldn't take 2+ seconds each time. That, and it sometimes seems to cause issues with the scenes. When I loaded a save that was during a conversation with the floating mask, where the background was supposed to be black, I saw the well-lit interior of a castle instead until I rolled back. If the decision to use Unity was made for the weird distortion transitions, then I think it was a bad choice, as those transitions get old very, VERY fast for me, and I was looking for a way to disable them. Having them for teleportation/rebirth/etc. would've been fine, but the whole scene sometimes twirls and twists even when a character moves or we get a new camera perspective within the same room.
Also, it would have been very nice if we had the ability to at least rename Alex at the start of the game. No need or logical reason to rename Peter - in fact, I think we never should have that ability - but renaming Alex should be a no-brainer.
Please, don't take these criticisms the wrong way. If I didn't like the game as a result of these things, I wouldn't be writing this comment. I'm pointing them out because I do care about the game. There are also some bold choices that I really appreciate. Having the player manually type out the name of the mask, for example, instead of having a simple choice, works extremely well and rewards those who pay attention. Similarly, I do like the fact that you actually only follow one of the two paths in the fantasy world, when you choose between playing as Alex or Lilith, as it warrants a replay. Most games would give you the illusion of choice but then only change the order of events.
Lastly, this is a fuckton of content for a 0.3 (and I'm not even done, I started writing this comment the moment Lilith sized herself up for the protagonist), so I'm very curious to see what the future of this project holds. Keep it up.