User blog comment:TraGiggles/Creating the Ice Age world with Starfruity!/@comment-4077536-20140413142615

I don't know if there is already a level gimmick, but an interesting one could be that a snowstorm would randomly go across the lawn and freeze some plants and some zombies, and during that time (about 5 seconds), you can't plant anything other than a Light Bulb to bring up the temperature for about 20-30 seconds (no snowstorms can happen during that time). Once the temperature drops, the cycle repeats.