Thank you! The original idea was chess but I realized that would take too long.

More than likely you couldn't move because you had a jump available (or a chain jump) that you weren't noticing. As per what is supposedly checkers tournament rules, you must take an available jump. If I had more time I'd've added indicators for which checkers can move and where but I ran out just after finishing the core game. Probably not a bug, I've been able to beat it a dozen times without anything breaking, but definitely something that could be improved.
Thank you for the comment!

If I had more time I'd've added an indicator of which tiles you can jump to- I think what happened is you had a chain jump available and were trying to take only one. That one trips up a lot of people. It is possible there was a bug but I played it a lot of times and I don't think that in particular is buggy, just not very intuitive.
Thanks for the comment!