just got a pretty significant update:
What's New in Version 1.06
Major update with many new features:
1) New maps: Africa, Australia, Fjords and Labyrinth
2) New Challenge System
3) UI and Multiplayer improvements
Each of the new maps has the same number of territories as one of the existing game boards: Labyrinth has 16 territories, Australia 24, Africa 36, and Fjords 48. To access the new maps you can either simply pay $1 for each, or beat a number of different challenges on the map to which it is tied. For example, one of the challenges required to unlock Australia is to totally dominate Volcano Island and win with only your own colour left on the map.
Some of the challenges can be tricky (challenging, one might say), but I finished all of them within two hours, so I'd say there's no real need to fork out unless you're impatient.