I love the concept! And it looks very cool!
Unfortunately it is very hard to understand how it works and how to play. I had to refresh the page and start again 7 times before being able to understand how to pass the first 4 waves. It desperately need some onboarding, explaining how to understand the laser direction (which took me a few restart to get), how to blend colors (did not understand that), etc.
The music sounds nice but audio could be improved with well chosen sfx. The UI can be improved too. Not being able to update the position of emitter you just added makes it very challenging to experiment and to understand what you need to do. I noticed an eraser tool but I won't get back the node I just put in the grid so it feels very punishing :(
It is a very cool concept, highly original. And it fits the theme perfectly. Good job!