There should probably be a confirm button on choice, so you can skip the 5 second timer for confirmation. Call it the "FINAL ANSWER" button from Who Wants to be a Millionaire.
I think odds are a weird thing for people to grasp. What's the difference between 1/37 and 3/74ths? That does make it harder to judge the effectiveness of a card.
Otherwise, nicely executed and no obvious bugs or anything. Good job!