Hi, unfortunately I couldn’t reproduce either issue. However, I’ve pushed a new update (0.3.0) which fingers crossed addresses both issues anyway. I’ve guessed that they’re either A) the font having issues or B) the extremely terrible way I was rendering the characters causing graphics issues or C) both.
I’ve added a fallback font (which should be used when missing characters are found, which would usually be the cause of squares in text), and it now renders the characters in a much more sensible way (which should hopefully also help with any performance issues). Also, I’ve updated the Godot Engine version for good measure.