That doesn't mean it should get a 1-star review though. Something being bad and not liking something are two different things.
If you don't like a game, that objectively is at the very least good, but doesn't cater to your taste, you shouldn't review it or if you do it anyway, you should be grown-up enough to still realize that it is good, even if it isn't what you're looking for.
If you're looking for a 6-seater with 3 tons of towing capacity and you somehow end-up testing a Bugatti Chiron and a Rolls Royce Phantom for that purpose, both cars don't become bad cars just because they don't do what you're specifically looking for. You were simply looking for the wrong thing.
In no way is Eternum a bad VN, no matter what kinks or expectations you have of it. The writing and the art stay top-notch, even if you don't like to read that much or you don't like the more manga style HS 2 comes with.
Sure, if you take "reviews" simply as a statement of taste, than you can give 5 stars to whatever you like the best, but that is not how I understand reviews.