Well, it's an educational game ;) but you make a valid point, visually the problem isn't clear, the outputs look the same except for the pointer being one cell further down, which probably doesn't read like it should be an issue. So what I guess I can do is visualize the null character in the output, then at least it should be clearer what's happened and what needs fixing.
ETA: And that's done. Looks much better and clearer, thanks!