Kyu's eyebrows are a bit too thick for me to see her as cute. I assume you were going for "cute," her aesthetic direction (wide eyes, slim frame, open face) doesn't read as "badass" or "tough girl" or "aloof". Making the eyebrows thinner and greyish-white to match her bangs would have unified her image's direction a bit.
I felt it was a little lacking narrative-wise. Why is it significant that the characters are cat-human things? What about the whole science-fiction theme? It looks very cool, but it might as well have been two American cowboys fighting on an old steam train, or Mafia gangsters fighting in a modern urban train. The cat-human science-fiction setting didn't feel artistically significant, just something that looked cool. I'm guessing that this was more like an exercise in animation.
The scene where LenZ jumps to the steel crane is a little too sudden. We never even knew there was a steel crane anywhere. Just showing us that crane somewhere, like in the background of one of the close-up shots, would go a long way towards making it read smoother.
The ending was a little sudden. It probably would have read just as well (maybe even better) if you cut out the little kiss entirely and just cut to black while they look at each other.