I can't rate it, because I don't have any humans I could experiment the game on, but I love the idea. I wonder: does the fact that one player is able to see the others fingers impact the game experience? If yes, maybe one should consider adding multiplayer to it (in the future, obviously not for a trijam) so one could switch the semaphore without the other player seeing one's finger moving to the left, but that would raise the question what prevents one player from perpetually switching the semaphore to red, preventing anyone from moving and ending the game? Maybe that's not problem as the players would be friends and would know better than just wasting everyone's time. The art and animation also looks great.