I have just finished playing The Missing Part, and, well, what a ride.
Overall I think it's a great game, definitely deserves the places on the list, and playing through. I will now go into an overall impression with unmarked spoilers.
Initially, I was momentarily put off by the intro, as many here, but after getting through the first time skip, the nature of the prologue got apparent to me. Despite that I didn't quite expect the second twist, and I think that the prologue being so short kind of robs those 2 events of emotional impact that they could have had. Partially due to the massive time skips and partially because the game is clearly set up with other LIs in mind and it almost felt like Ella and Maddie were getting in the way. Given that they seem to still be affecting the story in other ways, it's not directly bad, but it brings me to my second gripe.
What it boils down to is the game falling short of it's potential. I'm not saying that it's bad, it's very good, the character writing is splendid, but in the end so far it appears like another "choose your LI" dating sim, with a dash of grief, sorrow and wistfulness on top. That's great, but the issue I have with the LIs is that I just don't care about any of them. I would much rather play an AVN about a single father trying to raise Maddie, and *maybe* having one fixed love interest. Not on this website though, I doubt most of local population has any experience with fathers or fatherhood.
And finally my final writing nitpick is this quality that you see a lot of the time when characters just tapdance around things instead of saying it outright just to save it for dramatic "reveal" at the end, like why Sarah left her job, or who Lisa's mother is.
Production wise the game is also, in my opinion, falls a little short of the quality of writing, renders are good, but not exceptional, and the camerawork has the typical AVN feel to it. I liked the autoplay thing though and the soundtrack is the only soundtrack from the AVN to date where I actually looked up the title track. For a copyright free music it fit the story amazingly well.