This is a nice, very intuitive strategy game. The full version is a bit steep at $20 for such a simple game. The demo version only allows you the easiest setting, which is very easy to beat: computer simply waits and does not attack you; even if you make pathetic mistakes, you will still win.
The idea in the game is that you must make enough money to support a number of units, which you use to win more territory. You make one coin for each space you have in one 'territory' - it must be in one unit, undivided, and a cell that has forest growing it does not make money.
Forest can be cut down, but that takes one unit one turn. If there is a few cells taken by forest, it will start quickly growing. You don't need forest for anything, nor do you gain anything by cutting it down except for clearing a cell: basically, you want to cut down all the forest, as quickly as possible.
Units list - peasant: 2 coins/turn; fighter: 6 coins/turn; knight: 18 coins/turn; baron: 54 coins/turn. Therefore, a territory with 2 cells can support one peasant, territory with 12 cells can support 2 fighters, and so forth. You can accumulate money and for some time you can support more units using these 'saved' resources. To build a unit you have to drag it from 'info' screen, which you see by clicking on a city. A unit takes 10 coins to build. Of course, you can't build one if you don't have those 10 coins.
Peasant can take an unoccuied unprotected cell. If any unit is standing next to it, it's protected (or the village). Fighter can kill a peasant, or take the village, or take a cell protected by peasant. But it can't even try to attack another fighter. Knight can kill a fighter, and Baron can kill a knight or any other unit.
If you spend more money on upkeep than you have, all your units die.