Good Job!
Very good game! If you make any upgrades you should make smarter ai, if they need to attack the enemy by destroying snowmen first they just walk around, and it would have been cooler if it wasn't snowball theme, it should be military theme. Here's my map.
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[1,1,1,1,1,1,1,1,0,1,1,0,1,1,1,1,1,1,1,1],
[1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1],
[1,0,1,0,1,1,0,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,1,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,1,0,1],
[1,0,1,1,0,0,1,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,18,18,18,18,1],
[1,4,11,11,11,11,11,11,6,1,1,1,1,1,1,11,0,11,6,1],
[1,0,0,0,0,0,0,0,0,1,1,1,1,1,1,18,18,18,18,1],
[1,0,1,1,0,0,1,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,1,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,1,0,0,0,0,1,0,1,1,1,1,1,1,18,0,1,0,1],
[1,0,1,0,1,1,0,1,0,1,1,1,1,1,1,18,0,0,0,1],
[1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1],
[1,1,1,1,1,1,1,1,0,1,1,0,1,1,1,1,1,1,1,1],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]