This was a fun game. I think there's a way to get it to go almost forever -- got up to Day 35 and then let myself die. The idea was to never build a fence. Instead, invest in archers and fire/lightning.
When you hear the howl for night, move to where the fence is, and run to the left on the outside of the wall. The wolves will chase you, and your archers will aggro. If you run in an S shape the wolves will never catch you, and they will prefer chasing you to attacking the archers.
Because the archers never die, this lets you build up a huge quantity of archers, so much so that the game freezes for about a second when they start to attack.