There quite a bit to be improved;
It misses a lose condition. Meaning you can get infinite score by pressing random buttons.
Even being a very fast typer knowing the position of each and every key, its impossible to keep up after 60 or so.
The pause mechanic can be abused to get a higher score if you dont know the position of keys.
There is no restart.
Overall a lot can be improved, but you have delivered a game that works, and thats what counts :D.