Simple; addicting fun! Also glad the pace isn't all too hectic in this one, feels like a more leisurely version of all these cloud war games. Upgrades work well, levels are balanced in difficulty, and that daily challenge thing (wonder if that's random, or pre-planned?) is a fun addition. Would've been cool with an in-game stats screen btw, and highscores for all variables, seems a bit strange there's no count on rain upgrades, or green and orange, even though the others are there? Also, where's the snow?! Considering the title I was assuming it'd have a more prominent part in the gameplay.
Overall it was great fun though, not too long; not to difficult. Keep up the good work!
-cd-