Excellent Tower Attack game; I say "attack" because you are not only defending your kingdom, but you are also sending out attackers on foot to crumble the opposing stronghold. This is a very welcomed addition to the Tower Defense genre; I've seen it done before, but not this well. Your footmen upgrade based on increasing numbers sent out, but you have to balance that against ensuring your defending towers are doing their job. You see, towers on the field draw resources per second. If you spam towers everywhere, you'll have no gold left to generate units and you can't win without attacking. Brilliant system.
Some people may not like this game, but it is likely to be that they are playing it wrong. You have to control the ebb and flow, you have control resource nodes, and you have to react on the battlefield. Don't ignore spellcasting, because you think it's too expensive; it's a very valuable tool to thwart attacks and to make your own punch through defenses. Another warning, putting a bounty on enemy hard-points is extremely expensive; definitely worth it, but it has to be used at key moments when you're making a push (and be careful not to unintentionally trigger it).
There are tons of different units, all of which are upgradable through multiple tiers, so far. The graphics are period and perfect. Campaign, Skirmish, Defend, and Multiplayer modes are included. A very polished title from Paradox, one of my favorite developers on any system.