Hello Burndowntheworld! I assume you are a game dev beginner. Game jams are a great place to learn! You've done a good job. But the next step is to think about the game loop and add mechanics to keep players playing and having fun. For example, it would be great to add money for betting, add different horse statistics (such as their speed, health condition, how many races they have won recently, etc.), and also list different odds on the horse. For the money earned, the player could, for example, get into a better race, or buy tips from bookmakers. Everything possible can be invented.
Keep up the good work!