Build a mill
For completing all 3rd location levels with three starts
For completing all 4th location levels with three starts
Gather 6 workers on a level
Chase away 5 or more thieves over a game
Grow 10 or more trees over a game
Heal 10 units
Repair 20 buildings
Chase the octopus away
For completing all 1st location levels with three stars
For completing all 2nd location levels with three stars