Collected 1560 points, and had some fun, but also noticed some less than pleasant issues.
The arrow movement prevents two hand typing, and you need to rarely use anyway. Maybe moving left with F and right with J would have been better, as those are the typewriter starting positions, and using those would have reduced the break in the flow.
The random characters appearing under the enemies, even if there were 4 or 5 of them, wasn't to much fun. Typing games usually use actual words, because people read them faster and can type them faster. And with some silly words, you could have nailed the humor factor too.
The background image is your enemy. Drawing light letters on a background that has light spots is just unfair, especially with this font family. I typed "I" three times when I realized that it must be a "J" even though I didn't actually see it.
The repeating letters are less of an actual issue, more of a balance problem. Once again with actual words, and a set order of the characters, this would have been avoided.
All in all, I enjoyed this game, I love this genre anyway, it just needs more refinement.