Fun project! I had a similar project a while back, but my medium of choice was the Uno card game. I called it UnoScript [1] and it had similar mechanisms as color was an important factor. I also ended with a stack as the main part of the language, where different colors/combinations of cards could read from/modify the stack. Interesting how similar constraints can lead to some similar design choices!
[1](https://github.com/berlinquin/UnoScript)