It's a very straightforward game, not much to talk about.
The visual and sound response to typing is nice, the objective is clear.
After a couple of restarts, sometimes the game didn't recognise me pressing a key, which is a big deal when you are trying to type as fast as possible, yet sometimes you have to press a key twice.
It might be laggy due to performance, since I have other stuff running in the background at the moment, so perhaps it would be more responsive if this were the only thing I had open (on the other hand, I can't imagine this game is very resource-intensive).
It would be nice to speed-type things other than the alphabet, though (e.g. a paragraph of text), because keyboard layouts try to make typing real words easier, not letters next to each other in the alphabet.
If you cannot display the GameJolt leaderboard, there’s also the built-in Newgrounds leaderboard you can use, as long as you can call custom JavaScript in DragonRuby GTK:
https://github.com/PsychoGoldfishNG/NewgroundsIO-JS
Otherwise, no complaints. Let me also appreciate the detailed description and credits.
P.S.: Did you really type the entire alphabet in less than three seconds? :)