All of LDW's games are designed to be open-ended, so you can play any given game as long as you like! The Island Events will continue to happen, which can change the way things are going for your villagers. Once you get tired of your current game, you can do like most people do and play the game again on different settings and/or try different strategies. The puzzles aren't so stressful the second time, and puzzle 12 can be completed much earlier in the game than its position on the puzzle screen would suggest!

Believe it or not, I know people who have had the same village going for 6 months now.