How about a "Forest" outside the village where villagers get supplies such as foods and woods from? You can get different resource as the game progess? Maybe, a villager who wander into the forest and get lost and we had to find them?

Instead of just a Health Bar, how about a Bar that show how happy the villager is...

Things or options (e.g. Super Hard level) that can be unlocked by completing the game on different Difficulty.

How about collecting different Plants seeds to grow in spots designed for them?