Wait, developer! This is the game design police. You've been arrested for accusations that your ECS game doesn't pause, but closes the game window. We'll get away with a warning this time, but don't do it again.
Great idea. I love puzzles, but you accidentally managed to put together exactly the ones I'm bad at – Morse code and music :)
Anyway, it was interesting. The only serious issue is the lack of a truly fast rewind feature. Realistic, but inconvenient :/
The music track itself is good, by the way :)