This commit [1] seems to indicate that it's possible to change the font.
However, I can't actually figure out a way to do so; ":set guifont" doesn't appear to work.
[1]: https://github.com/applidium/Vim/commit/be572d759e857de58453...
Hi :-) I added font support pretty much at the last minute. Here's an example of something that should work ":set guifont=Courier:h14"
It doesn't seem retina optimized. The font is horrendous on my iPhone 4.
The font is pretty ugly too - I can't easily tell the difference between q and g.
However, it is a neat hack, if not very usable.