My instinct with this kind of game is to play it like Doom. Get in the enemies face and shoot as fast my fingers will allow. Don't give them an inch toward my precious sunflowers! The snowmen, however, were gravely overestimated. On my second playthrough, I simply watched in mild bemusement as they slowly, slowly approached my sunflower garden, occasionally slightly altering their course, or even thinking twice about the whole operation and turning back the way they came. Such cowardice could not be stomached, and I killed them all again.
Good entry! I loved how charming the snowmen were, and overall the artstyle was very nice. I had fun trying to see how far I could kill a snowman from with the arc of my water balloons.