This is honestly just awesome. This is such a fully realized game that I wouldn't be surprised if someone told me that this wasn't a Game Jam game.
The gameplay is simple yet challenging and deep. The pixelart is beautiful, coherent and easily understandable when playable, and the added details like the debris in your snowball and the particles enhance the look even further. The music is wonderful, and I love how the theme during gameplay builds onto the menu theme. I also like how the game communicates what you can actually destroy and what not. You really thought of everything here, and it shows. All these aspects really form into a really tight, enjoyable package.
This is exactly one of the gems I hoped to find in this Game Jam, I really hope you crack the 20 votings. Keep up the great work!