While an entertaining game, Defend your Castle for Wiiware is too much like the free online version to spend 5 bucks on.
There is a few things different about this version of Defend your Castle, just enough to keep me interested in the Wiiware version over the online version. The addition of being able to play with up to 4 people is great, and the King aspect adds to the competiveness (whoever kills the most stickmen controls the upgrades and spells and such, thus being crowned King). Also, there is no gore and the game has a more playful, paper-drawn atmosphere to it, which I personally like better, but some people may not like the change.
However, just like the free online version, most of the upgrades work the same way, and all you do the whole time is pick up stick men and throw them (or cast an occasional spell for the more feisty stickmen units such as the giant ones you can't lift off the ground)- just like the online version. And, playing it for extended periods of time really hurts your wrist. My wrist started hurting when I made it to level 25. I guess the physical pain your recieve from playing this game adds to the competiveness- how long can you go before your wrist starts hurting?
Overall, an okay game to spend 5 bucks on. But its just too similar to the free version. But if you want to play with Wii controls and up to 4 of your friends, its a decent spend.