I haven't played a game by NiiChan before, but I'm definitely a fan of this dev's work now.
Came into the start of the game not expecting a huge amount of content (Episode 1, Part 2), and looking at the tags like harem, incest, and virgin, and the choice of rendering... well, you can't really argue that certain expectations were already there. Boiling it down to these few parameters, there's a lot of these types of games on F95 and other forums.
What NiiChan has done with this stereotype is give it a sprucing up. A new look. A new dynamic. This is, frankly, pretty good stuff. Interesting approach to a harem story and I'm really only through part of the first part of Part 1.
The characters are interesting and have their own backstories, though as you can tell by the title and the first few minutes of playing, they're interwoven. The MC knows these characters, and though the exposition is a little long -- I will get to that shortly -- it does sufficiently tell what has happened in the past.
What helps MBIML push this into a "must watch" game is the story. I won't go into spoilers until later, but it has a good idea so far that, while still in the realm of "this is an adult VN and certain embellishments are expected", puts a simple but deep twist on previous, and less interesting, games.
So, while I think the game is quite strong,
especially for a recently released game, it does have one thing I wished it did better: I wish it had revealed the plots around the girls a little slower. I understand the desire to get the idea out there and get your audience entranced and interested (which was well done, by the way), I feel it could have been used for a greater effect.
For example...
I could be wrong about this, too. There could be many, many more twists in this game that would throw all this out of the window. Who knows what's going to happen? Only NiiChan.
TL;DR: Very good and promising start. Interesting characters, intriguing and enrapturing story. Renders are good, animation angles and sequences are quite good. Definitely worth a look.