Thank you for a good and very playable game.
It took me several tries with many different seeds, but I made it at last. 8000 points on seed 5706121. I like the simple but cool rotating cubes at the end.
I also like the non-minimized source code. It makes it instantly discoverable without having to find your repository (https://github.com/Kiryhas/memechain).
Looks like you did it without any external libraries which is cool! It looks clean and readable, and proves that developers don't need to download huge dependencies to create these types of games.
I have one minor suggestion. It would be great if you made the highlight a bit clearer when you are hovering over a matching cube. Sometimes it can ba a bit difficult to hit the correct spot. Maybe you could highlight the hovering cube as well in addition to the outline?