A good idea for a game! I hope it's okay, but I do have the following inputs:
* 1. Typing random gibberish isn't that fun -- it's more entertaining to type words in reverse for your own language. I know this can be a bit iffy to just target one language, since there are so many, but I'll say that typing gibbering in reverse using only standard ASCII isn't quite as good as it could be. Pulling from a generic dictionary probably would've been good enough.
* 2. Picking up a keypress should only tie it to "one" of the current on-screen words. I noticed that it would solve for multiple words _as well as_ multiple repeated characters. For example, if you hit "h" and there was a word with "h" and another word with "hh", it would solve for both. This doesn't feel quite right in my opinion.
However, I loved the idea and am only nitpicking. Oh, also, typewriter sounds would've been cool as well.