It's good, but a 50% success chance at the start can be a problem. I started the game dropping down to -6... Also, 12 seconds feels a bit too slow for the beginning. A slow start makes sense, but it feels like this should be handled differently. I think it's a good concept, but if you get a bad start, the game flow suffers a bit. Still, it's a super cool and awesome game for a game jam!