Awesome Game! Excellent Crossover!
Here are a few tips for survival:
1. Fortify your defenses as much as possible, but DON'T rely entirely on them!
2. Go after the faster enemies first, i.e. R.C. Car, ball and chppers. And take out the choppers at all cost. They can bypass barriers.
3. Upgrade the Shotgun and Chainsaw first when available. They're excellent for thinning out a huge crowd.
4. Keep an eye on the presents. If they stay still for a while, they contain powerups.
5. Try not to open too many presents at once except to get the Present Frenzy medal. They could be power-ups which you could've saved later on, or you might get swamped with more enemies than you can handle at the moment.
And again, Awesome game. People might find the whole Halloween-Christmas crossover controversy, but when this game's so addicting, WHO CARES? Once you start, I can guarantee you'll be playing it for hours.