The low-poly art is really nice, i love the colors you have chosen, and the fire animation!
I think you could have implemented some way for us to regain ammo slowly over time, cause once i ran out, there was nothing i could do except stand int eh way of the snowmen so they could kill me.
It would also have been wonderful if there was some way to chose your mouse sensitivty, since it was very hard for me to get any precision with the default settings.
Didn't hear any sounds, it would have greatly improved on the experience.
Very good effort though, working on your own. Keep up the good work!