Wow, what a mood!
Honestly, you've done such a great game when it comes to sound design. As a sound designer, I really enjoyed how both the puzzle mechanics utilizes audio, I haven't seen anything like this before.
The first puzzle was initially too hard for me, but later I realized that Q and E could be used to change the radio channel and I managed to figure it out without hints. I would've loved to see some hints in the UI in terms of the keys available to use.
Game play felt solid, you had some legit puzzles and you used audio and the theme very creatively. I could easily see a fully fledged game built around these types of environmental puzzles. Reminded me a tiny bit of The Witness.
Thanks for making the game :)