Thanks for the reply. You make some good points.
The thing is, I don't really think choosing not to translate "kuso" as "shit" is really censorship, or necessarily dubious in terms of quality/accuracy. Yes, they both mean feces, and yes, they are both often used to show exasperation. However, they're still not totally identical. The differences are very subtle, and we could discuss them for a long time, but suffice to say that those differences can be important.
Anyway, the word "kuso" appears in the game-text 14 times. It would strike me as plain awkward if these guys said it that much. That's my interpretation of what kind of people the characters are and how they express themselves, as well as the tone of the game as a whole. I will, however, consider putting "shit" in once or twice in the most extreme of those 14 situations, depending on how things look when I'm done with the first draft.