I love the SFX at work here, y'all did a great job! I wonder if the background music might not be a little bit bombastic for a puzzle game, but that's just my own aesthetic preference.
I think you could have unpacked Rule 3 a little bit to explain just exactly how cells die -- that took me a little bit of time and some careful reading between the lines to grasp.
That, plus I think just a little bit of visual polish on the step-results at the bottom -- make it a little bit larger maybe, and tweak the Question Mark UI elements to make them look a bit cleaner -- you'll basically have this game in the bag. Great work!