How's my Simon game?

Please let me know what you think.

I’ll be the first to admit that my art chops are not what they could be, but I had a TON of fun working on this project and I am quite proud of the code I’ve written, although I know it’s not perfect and probably has some bugs somewhere that I didn’t catch. That being said, I’m very happy with the end product and would like to know what others think. Visual critiques are welcome, although I am most interested in code-related feedback.

Thanks in advance!