Awesome game! Really loved the UI and the small details (e.g. the lighthouse at the back). There were a couple of things that I noticed. In the frequencies, it is hard to distinguish the "1" from the "7". Though you it's a mistake you only make once, it would be nice to disambiguate them. Also, it would be really cool if there was a WPM slider, which let you configure how long you need to hold to send a dash. I found that it was a bit longer then I would have expected, and it would also let people go a lot faster if they got more experience.
Finally, this would be an awesome tool to help people train in morse code, if it were further developed!