Other than the dev seemingly completely forgetting about Rachel (only one with no solo ending/repeatable harem events, and still a placeholder text saying her story will be expanded "in the next update") I honestly feel fine about the ending. Is it the best ending to one of these games? Not by a long shot, but at least an attempt was made to properly wrap most things up.
That being said, the fact that the dev puts a tease in for their next game when there's still work they could have done to polish this one doesn't exactly leave me hopeful for how that will turn out, especially if, assuming the naming style seems to match this one, it will be even more ambitious in scope.