Very nice game, I was slightly confused at the beginning because both 'caps lock' and 'start' were green but i figured that out easily.
It would be nice if there was as option to turn off the can lines as well as the crt, and it would also be nice if there was a 'clear all' option. a few times when I made a mistake I had to uncheck a lot of keys and an option to just uncheck everything, or rest the level would be great.