Challenge Go is now available in touchscreen format on these platforms:

Android: https://connorhawke.com/challenge-go-android

iOS and macOS: https://connorhawke.com/challenge-go-apple

Windows: https://connorhawke.com/challenge-go-windows

The online high score system is shared between all platforms.

I hope that those who play this game have as many moments of fun and frustration as I had creating it.