Beautiful.
The site should be more explicit about which characters are covered. I understand it's only ASCII, right? Although the example shows some currency signs that are definitely out of the 0-127 plane.
It would also be appreciated if you could suggest a fallback font for those glyphs not present in Myna, so that if I ever need to include the word "naïve" in a string, for example, the "ï" won't look as an alien character.