With the current fixes v.0.2.1.5, a complete normal playthrough takes roughly 2.5hours. This includes no cheats, no nights skipped, cumming inside Yuna and taking her to the beach. Imo that's a good amount of playtime for the content that is currently available. Neither the running game nor the night sessions overstayed its welcome.
That might change as the nights are getting longer and longer though if there is nothing new to do. From the preview blogs there are still a few things planned/worked on to help with that.
In the current state the game is close to being perfect to be honest and there are only few things I would like to see added to improve things more on the immersion side of things.
-female climax could be a bit more visually (juices) / audio (moaning a bit louder than the moans before) impactful.
-peeptube correlating with what actually happened in the night session
-Kaede is calling the MC out by name on peeptube, which raises problems in the current state of the game (wouldn't she tell Yuna?) but could be a mechanic for the story later on
-more combinations of different existing actions/states. for example, the mouth options could be used to clean up Yuna when there is squirt or sperm, or make her swallow those via kisses.
Due to the great foundation of the game, I'm expecting the community to be pretty split and vocal about the direction of it soon.
Personally I am more on the gaming than the fapping side of things. So I would welcome an expansion of the suspicion events that were currently added (unlocking the door for her/Kaede peeptube). Like a real mechanic which forces me to be careful about putting clothes back on before the night ends to prevent a bad outcome for example.
But I am well aware that punishing/bad end stuff is not very well liked by the casual players. Not sure if it is worth your effort to put something like that in for only like half the people playing the game (maybe making it toggable for people who don't like it).
Another behavior mechanic I would like to see, which might be more welcomed by a majority of the players, is making Yuna more horny for the normal daily events. Like when we leave her heart-meter topped out at the end of a night session instead of making her climax. Could be solo-scenes or her being more open to MC pushing his luck in those events.
Either way, thanks for making the game.