WellyWales: As said, that might give the player going first a bit of an advantage.
Perhaps it's better to have a rule that the second player cannot play his first move adjacent to the first move of the first player.
However, I don't think the second player has that much of a disadvantage - certainly less than white has in chess. Yes, the first player has the disadvantage of having to make a blind shot - but there are only five enemy frogs. He's more likely to make a shot right next to an enemy frog, revealing a non-zero number, leaving the second player to make a blind shot.
(hide) If you are waiting for your turn, click on "change" next to the "refresh" on the main page, then set refresh the page to 30 seconds to get your turn to move displayed faster. (Servant) (show all tips)