Here is the full list of all 13 Snow Madness trophies - there are 9 bronze, 3 silver and 1 gold.
Roll with snowball.
Use Portal to teleport in the map.
Kill the wizard.
Take a life power-up.
Kill level 10 boss.
Kill level 20 boss.
Kill level 30 boss.
Kill level 40 boss.
Kill level 50 boss and finish the game.
Finish the game in easy mode.
Finish the game in medium mode.
Finish the Game in hard mode.
Play multiplayer mode.