I absolutely adore your suggestion about 3x3 tile groups for some advanced plays. That's bound to add some nice depth, and a higher skill ceiling.
I'm a little unsure about the "rotating tiles" idea. But not because it's a bad idea, rather because it's a little challenging for me to do. However, I can look into it. It might a nice addition.
About the audio and SFX... I was just lazy, to be honest, hahaha.
Been having a lot on my plate lately, so I didn't bother to add sounds, animations, and VFX in general. I figured that as a prototype it got the idea across well enough for me to get feedback (and on that front, it has been pretty successful).
I'm really glad you enjoyed our game!
The overall feedback has been so great, that I'll definitely turn this game into a full release at some point in the future.