Thank you for playing my game, I'm so happy to hear how much you enjoyed it! I also appreciate your feedback and definitely agree with your recommendations. Currently, the running minigame won't end until all of the horses are caught, but I do think a final countdown timer would be a fair mechanic to end the game. I also agree that the wrong color horses should run with you (or at least run past you one time) because they'd block the cacti! I have been thinking of some other mechanics to turn this into a full game, and if/when I do I will let you know!
Thanks again for playing and the feedback!!