As the transmission says, you are in charge of keeping the hotel safe from the incoming swarm of abominable snowmen. This isn't a tower defense game with waves of creeps though, it is one of those 'tap to kill' games where you have to defend your hotel from the masses of snowmen that want it gone.
The snowmen in Snowtel come in all shapes an sizes, some have force fields, some fly, some are really quick, but they all die the same. All you have to do is set your iPhone in a comfortable position and then tap like an insane person. My personal method was to tap at rapid speed along the edges and then catch any that broke through my death tap line, but I'm sure any method would work. After 31 levels of snowman blasting chaos you'll get really good at it.
In the end, Snowtel really suffers from a lack of variety. The concept is fun, the graphics are wintery and cold, but there just isn't enough variety to make me want to play over and over. What would make Snowtel better would be some add-on RPG elements. Let me spend some hotel dollars to purchase some landmines or an auto-fire cannon/AA gun that I can perch on top of the hotel. Little things that change up the gameplay are critical, and Snowtel kind of misses the boat on that. If you are just looking for a quick holiday themed romp though, you may get a kick out of popping the snowmen in Snowtel.