In something like 4 hours, I could retrieve sprites I made before and make them triggerable notes.
I endured a lot of pain when I realized that Collider2D triggers
OnTriggerEnter, and I think I spent an entire hour figuring out why my colliders
did not trigger in my scripts.
I also used a timer, the goal here is that when a small note light is triggered, it can only be
active for a certain amount of time.
This is important, because I want to make the game something like a "Simon" game.
The rest of the time was spent improving a bit how the scripts are ordered, how the layers works (by the way, I also discovered sorted layers, this is awesome!), and re-designed just a bit the light trace.