The bull is pretty decent with his own personality and responsibilities as your boss. Most importantly, he is not an ugly bastard but a good looking playboy, whom you can believe girls could fall for and expect to be good in the bed. He is plenty mean the way girls find it attractive, but also knows how to treat a girl well if he wants to.

Kana is loveable and there are several events of doing normal couples stuff, but as she gets corrupted her thoughts warp and she starts rethinking her relationship with you. She even catches on that you're not protecting her and even enjoy seeing her being taken by someone else, while she is trying her best to endure it and keep on a facade.
She is her own personality, with her own schedule and thoughts that can slowly change depending on the player, which is unparalleled in these kind of games. Her art is very good and wears several cute outfits in the game as well.

The world feels alive and responsive, with bystanders commenting about Kana's whereabouts and clues on what's going on. You can even call Kana to go on a date and she will answer depending on her schedule and plans for the day.
There is an ever present time and performance pressure, as it's not obvious from the start how to best do the work on the different maps, or what's Kana doing during the afternoon. Keeping the player on its toes is very difficult, but this game manages to do it.

The game perfectly blends the elements of both netorare and netorase. You're not actively whoring your girl out, she has her own will and personality. The most you can do is prevent being cucked by paying attention to her and putting in the effort of finding her in time. There are different endings depending on how corrupted Kana gets and in parallel, how depraved the player was willing to go.
Nebel perfected the gameplay loop and mechanics for NTRS games and I've yet to see one come close, let alone emulate or surpass it.