I gotta agree on that. That second to final scene was a complete whiplash of emotions and it was surprisingly done right. Granted the developers were from Ukraine so it made sense how they handle "it" pretty well.
With that said I disagree with your other points. The game have told us from the very beginning Kim's life in Pawer Hill was rough. From a very young age she was separated from her parents for unknown reason. Throughout her life the only person that was there for them was her best friend Sally who also has parental issues likely due to the fact that she has a crippling drug addiction, nevertheless she decided to live with Kim in some cheap hostel. From a very young age Kim sold her flesh for a living, but when she found herself being in brawls more often than work she decided to turn the fighting into work and she was really good at it. One faithful evening opportunity knocked at her door, Karlos a recruiter for fighting tournament saw promise inside Kim and gave her the opportunity to participate in a brutal sex fighting game aptly named "Erotica".
What I assume was the result of your reaction was due to the comforting style of art that the developers utilize. There was no point in the story where the main character nor should the audience be comfortable at. The ending was even foreshadowed three times, so I don't know what kind logical conclusion you'd want. At the very least I praise the developers for setting the tone early and creating another captivating story in a short span of time and I would love to see it until the very end.