I had hoped that someone would mention what specific thing was missing, because as far as I know it's trivial to do anything one would want to do when making games already. That is, it is very easy to accept UTF-8 input, output UTF-8, munge UTF-8 strings together prior to outputting them, compare UTF-8 strings for equality, and so on. If the game needs UTF-8-aware strlen (for limiting the length of a field or alphabetizing things), it is like 10 lines of code.