In the context of ostensibly one-person-show indie adult VNs, OIALT is a masterpiece, if only for one very specific reason:
In a slew of titles on this site using scope creep as a convenient excuse to become vehicles for milking patrons year-over-year, OIALT has accomplished exactly what it set out to: tell a compelling, sexy, and funny story with meaningful choices over 10 parts, with room to keep growing in the future.
With the successful conclusion of the main plot, it's become self-evident that not only was the project rigorously planned out start to finish from the very beginning, but - and more importantly - the developer had the discipline to stick with that plan without generating a million new and "wonderful" ideas in the interim of development, burning themselves out in the process and all but guaranteeing the kind of delays you can't go more than three clicks from this review without finding.
Exceedingly rare with this style of game or not, while this is all very dry and boring stuff, it's also hardly the game's only quality. Overall, this is the Goldilocks indie adult VN. Not too long nor too short. Not too horny nor too much story, only a little gory. No skipping entire in-game days to trigger the next event. No grinding. No absurd fridge logic. No crappy stock music (very good audio design overall actually, do NOT turn the sound/music off). Just a solid, fun ride through a guy and his (step-)family and friends' battle against evil.
No, the plot doesn't have the grandeur of Fate/stay night. No, you won't find the kind of character development Lessons in Love is working on. No, you won't find the (riveting, if you're into fishing) gameplay of Hero's Harem Guild. No, you (thankfully) won't find the same bottomless wellspring of dumb humor as in Four Elements Trainer. No, you won't find the same amount of lewd content as in Being A DIK.
But only one of those games is finished or even close, and none of them are fair comparisons, because in terms of a complete package, where you get a balance of everything without needing a week to find all 5 endings or 12 years A Slaveof development to wait for, I would really love to hear of anything comparable.
...And if this is what Caribdis is capable of, I can't wait to see what Scylla has in store *ba-dum tss*