I do too much typo for this game but it's really fun aproach of the theme, the letter running is a really funny idea
For feedback: It seems the return to menu button when you lose don't work.
When you lose the defeat screen could be improve, actually the change to black screen is too abrupt just a fadein/out would be better rather than direct change but with the theme why not invade the screen with running letter ? (just an idea since i found the runing letter really fun and cool and since they escape that could fit i think)
I also noticed that if you type too fast the same letter on running letter it count as typo and you lose some time wich can be annoying at higher level