Summertime saga, i get that decent 2D games are exactly that easy to find but, it's meh for me, very little going for it, it's not a bad game but it's definitely not a standout good game either.
Underrated, Monster girl dreams, best monstergirl game I've ever played partly because it's far less extreme than many and has great writing and characterisation, it really sets the bar for text oriented games IMO.
Ethan's legacy, the best unfinished VN that i've seen, the dev got caught by a story spiralling out of control IMO, pity he never got past the first of three acts, it could have been amazing.
Midnight Paradise, gets a lot of shit for the teething problems it had in the early stages, going from a very buggy unity version to then get a full overhaul into Ren'py, where it should have been from the start. Even now people are still saying "no sex content, boo, game is shit", yeah, it's far better than it's rep would suggest so without doubt it's underrated.