Thanks guys, glad you enjoyed this Christmas mini-game! We recently ramped up the difficulty so it gets progressively harder (faster / stronger enemies) as you get into the higher levels. Definitely had a good time making it and I will be sure to put up the new 8-bit "Rockin' Around The Christmas Tree" as an mp3 sometime soon.
Be sure to play the game on Newgrounds so you can collect all the medals for your account!
By the way, somebody posted a pretty solid guide for playing the game and I thought you guys might like to see it: