I beat all three tracks, and I had a lot of fun with them. There were two attack patterns that killed me OVER and OVER though:
1. Mid-way through level two when the squares start exploding into fireworks
2. Near the end of level three when the sin wave starts going super crazy and flexing with the beat
Something about these two patterns felt extremely frustrating because I had a lot of trouble understanding/predicting them. I ended up beating both of them not by reaction, but by memorizing where I needed to be on the screen to not die. It felt like a cheesy strategy and a really steep learning curve.
It's definitely a fantastic first rhythm game, and the music slaps. Even when I had to retry the same levels over and over, I still always enjoyed the music. Great work!