If a game comes along with a producer like "Arbeitskreis Spielkultur" (sounds like some typically German dry official office), you should be careful. If the plot revolves around Norse mythology, the expectation of some completely non-understandable crap made by roleplaying geeks.
The surprise that Wodan is actually a well thought-out, intriguing puzzle game is even bigger with these prerequisites. A map made of hexagons is waiting to be painted completely in one colour - preferably yours. That's done by moving small viking figures around. Every spot you move those to immediately changes colour. Problem: the up to seven enemies are trying the same.
Each figure has a control radius of one hexagon in each direction, and equally strong enemy figures can't enter it. That's the way to defend your own part of the land. If there are 'equally strong' figures, there have to be 'stronger' and 'weaker' ones as well, of course. These consist of combinations of up to four basic figures, and they're of course blowing away their weaker counterparts easily.
The number of available figures is determined by the size of your land. You get one point for each hexagon of your colour which isn't occupied by trees each turn. A new figure costs ten points, and depending on its strength, each figure has regular costs for upkeep per turn as well. For a more permanent defense, towers can be built. These successfully stand against the first two levels of warriors and don't need any upkeep.
The 'battles' are completely without random elements. This is why Wodan isn't so much a tactical wargame, but more of a nicely presented puzzle. On the long run, the random maps and the AI controlled enemies won't be demanding enough, of course. At least the latter problem can be solved by the networking options. To get there, you really should start training a little as soon as possible...
No download? Although the game may be copied free of charge, its license explicitely prohibits hosting it on a website. Please go to the official website (see related links) and download the version of your choice from there.