For the open source category, you'll need to have a README file and License file.
What an interesting concept. Lovely take on the theme. I'd definitely love to play with another person, yet playing against yourself is still really fun. The implementation of the timer at the top of the screen is different and subtle. I don't mind this.
Music fits in nicely with your game. I enjoy co-op games so it's cool that this is working together and competing against the time, rather than competing against one another. Great work on your submission.