Make frog's tongue flash. Swamp will go back to daytime, score will return to zero. Your frog will be out of business. You'll have to WAIT until he swims back to the pad before you can try for another score. Time your jumps so that frog gets closest to fly at the highest or lowest point in his jump.
Game time is three minutes.
Watch for the changing sky - from daylight to sunset and darkness. And whenever any frog is not moved for 15 seconds, computer will take over.