Defend Your Castle was originally a flash based game, that was remade for the Wii's WiiWare on May 12, 2008, where it was the cheapest of the six launch titles at only 500 points, or $5. The game has players defending their castle by picking up the opponent's soldiers and dropping them in the ground, and performing other actions to kill off the adversary. In 2019, the game was ported to the Nintendo Switch.
During the game, the opposing army will send out troops to take over the castle. Once an enemy is close enough to castle, they'll start to attack it. It's best if the player dispatches of the enemy before they come up to the castle, though they will still be able to when they're attacking. The most basic form of attacking is picking them up with the game's cursor and dropping them. As the game progresses, however, the player will be allowed to use more advanced weapons including arrows and even magic, and upgrade the castle's defenses.
The original WiiWare version supported multiplayer with each player earning points. This feature was dropped when ported to the Switch.
There are various different enemies in the game, with some appearing later in the game than others. The enemies in the game include:
- Standard stick figure: The most common and basic enemy, they'll appear in every stage and simply run up to the castle and start banging on it. To kill one the player simply needs to pick him up and drop him into the ground.
- Popsicle stick figure: These are stick figures that wield Popsicle sticks. They'll ram the sticks into the castle, dealing more damage than a standard stick figure. They are dispatched in a similar style. These start appearing on level 4.
- Pop cap stick figures - These guys roll bombs to the castle, and can be killed by simply touching the bomb. Any enemies near by will also be killed by the blast. They start appearing on level 8.
- Pop lid heads - These guys resemble the cap of a bottle of pop. They're very large and can't be picked up. The only way to kill them is to either click on them multiple times or make a bomb explode near them.
- Catapults - The hardest of the enemies and unarguably the most dangerous, these catapults will start to appear when the player gets to the fortieth level.
The WiiWare remake includes greatly updated graphics. It resembles something an elementary school kid would create, including a multitude of purposefully misspelled words (such as changing "health" into "helth") and making the enemies and castles look hand drawn. Even the enemies' most basic weapon are Popsicle sticks.
Because the developers wanted the game to be appropriate for everyone, they've removed the use of blood, which was present in the PC version. Rather, the stick figures will just be planted into the ground and shortly thereafter vanish.