I was late to sleep because of this, thanks! One suggestion, allowing swipe on touch devices would feel a lot more natural than tapping each square, which was a bit error prone. Either that or make the hitboxes a bit bigger.
Thank you for the feedback! The hitboxes are already quite big on mobile (only a 2px gap). I have implemented swiping though, let me know how it feels :)
Swiping makes this much easier to use and even more addictive. Nice work!