That just seems wrong to me. Friendship > horny shouldn't matter; it should be friendship > (some number). Horny 50 friendship 49 and she leaves, but horny 0 friendship 1 and she stays. Not very well thought out on the dev's part.
The ending did seem a bit rushed. There are some things I would have liked to see. The way it's set up, the "choices" after that point of the game don't matter. Not really, anyway. You might get 1 or 2 variations of scenes in the epilogue, but overall, it's the same regardless of what you pick after that.
I would have loved to see an outcome where you can either win Christine back after she gets taken from you (NTR route), or don't get her back, but get revenge on Robert/Silver and get them sent to jail. This would have worked especially well in the friendship NTR route. Most, if not all, of Christine's dialog (and inner thoughts) if she has more friendship points and dating Robert/Silver is very negative. Like how she doesn't really like how they're treating her, but goes along with it. Couple that with how excited she gets when she messes around with the MC (either saying she never came so hard before, or how MC is bigger than Silver), it seems to lay the groundwork for her going back to MC. The way she's speaking about them makes no sense that she wouldn't help take them down for weapon trafficking. It's like, "I don't like these guys, and MC is so much more fun to have sex with. But I'll still protect these guys anyway, and ruin my relationship with MC."
This is just me, but when it comes to NTR, having the girl addicted to sex with the "bad guy" and the MC not being able to satisfy her is a large reason why NTR works. So, when it states pretty clearly that she enjoys sex more with the MC than with Silver/Robert (in the friendship NTR route), AND she doesn't like the other guys, then they should lose their power over her and it doesn't make sense in my mind why she would still stick up for them. I just would have liked the option or choice to see a different outcome instead of being locked into 1 ending (with a slight variation) for the NTR route.
Overall, though, I still really enjoyed this game, and playing through the different routes.