This is one of the craziest game modes ever, but it's awesome nonetheless. It's like freeze-tag, except with guns. You get a snowball launcher, which lobs a snowball; an ice ball launcher, which works like a gas grenade; a shovel, used to kill frozen enemies and revive frozen allies; and a snow bomb launcher, which works like frag grenades. Left-clicking fires your weapon in a rough arc. Right-clicking launches your shot much faster and farther.
The objective in this mode is to freeze your opponents and eliminate them. Each team has a set number of respawns, and you win if you reduce the other team's respawn counter to 0 as well as kill all members of the other team.
To do this, you have to shoot snowball projectiles at your opponents to freeze them, and then hit them with a shovel. Be aware, however, that the snowball follows a parabolic arc; it might be easier to think of it as a grenade with a long range and a tiny, tiny blast radius. The snowball explodes on impact, causing splash damage to anybody near it. You don't have to worry about ammo, because you are given an unlimited amount.
Because the snowball follows an arc, instead of a straight line, the trick to hitting is to aim high and lead in front of where your opponent is moving. If he is strafing back and forth, aim away from your opponent into where he will be stepping. Think of the lines between you and your opponent in terms of a V, with yourself at the crook and where your opponent is moving at the tops of the V. If your opponent moves toward one end of the V, aim for the other so that it hit when your opponent moves toward it.
Additionally, if you see anybody with a "Help!" bubble above them, smack them with a shovel. The "Help!" bubble means they're frozen and vulnerable. Hitting a frozen enemy kills them. Hitting a frozen ally unfreezes them and gives them 50 HP. A frozen ally will unfreeze automatically after 10 seconds, but they will only have 25 HP. Frozen allies also make great bait; let them stay frozen to lure enemies who want to shovel him, and then freeze the enemy before he gets the chance. Frozen enemies also make good bait, for similar reasons. Frozen players can also be used as obstacles; you can actually hide behind them to keep yourself less in view to throw off your opponent's aim. Don't forget to use splash damage to your advantage. Aim for your opponent's feet if you feel you would miss their body.
In this mode, the shovel has only one use- unfreezing your team and smashing frozen enemies. It only deals damage to frozen enemies; moving enemies cannot be killed with the shovel.
The ice ball launcher works as a gas grenade; it lobs a ball of snow that explodes into gas when it lands. It travels about the same distance as ordinary snowballs, and is actually quite useful; the snow it releases is not very visible, so you can aim and shoot at your opponents even when they're in the snow-gas. It's great for getting an advantage over a single player, or evening the odds against multiple, clustered enemies.
The snow bomb launcher works as a frag grenade; when you fire, it lobs a snowball with a red tail that will bounce and roll slightly before exploding. It has a fairly large blast radius, just like an ordinary grenade. However, be aware that it is a launcher, not a grenade. Therefore, if you left click, it will shoot. You can't hold the snow bomb in and release it when you're frozen by an enemy.
One final tip: your snowballs leave a trail that is highly visible to both you and your opponent. Use this to your advantage. Send a snowball up into the air to lure your opponent in, or watch for flying snowballs to figure out what your opponent is doing.
Best of luck to you all, and I hope you have as much fun as I do with this game mode