This week I played two theme-only, tower defense games: Battle Cats and Plants vs Zombies. Tower defense is a game genre where the goal is to defend your territories or possessions by obstructing the enemy attackers. It often involves stopping enemies from reaching the exits by placing defensive structures on or along their path of attack (e.g., playing defensively) or offensively by attacking the enemy, and capturing their territories or possessions.
The theme of Battle Cats is, you guessed it, cats. The theme of Plants vs. Zombies is: plants and, you guessed it again, zombies. I suppose one way to reveal the theme of your game is to make sure it is reflected in the title.
Without a theme, a tower defense game becomes dry and mechanical. They are impersonal and not engaging. They fail to capture the players’ imagination and attention. Imagine a game where the only theme is to be a “player” with the option to “attack” and “defend” against an anonymous, unnamed “enemy.” I’m pretty sure no one would be talking about that game let alone choosing to play it.
So, game designers innovate and add a transformative layer of “theme”, which instantly brings the basic mechanics and dynamics to life. In Battle Cats, you are on “team cat” and produce cats to attack other animals that may be threatening you like snakes, for example. By winning more and more levels, you continuously lock more exciting cats, enemies, and weapons which adds challenge to the game.
Plants vs. Zombies is one of the most addicting games I have played in a while. Players are on “team plant” and must defend the house by attacking (e.g., throwing Split Peas) and defending themselves (e.g., using a Pumpkin to protect plants). While tower defense is not my genre of choice, the theme and exposition of the characters kept me on my toes, interested, and eager to continue to different levels and environments like the pool, fog, and roof. I finished the game in a few days and grew attached to some of the weapons, like Spikeweed, Squash, and Tangle Kelp, which I used in almost every level. I also enjoyed seeing the variety of Zombies and learning how to best defeat them. Crazy Dave is also an endearing character and I looked forward to reading silly notes from the Zombies. These small details together told a captivating and ridiculous story that was highly entertaining to watch unfold.
Cats, plants, and zombies are all relatively simple themes. This is not a coincidence. All players will likely have a mental model of these three concepts, and the game designers simply leverage that knowledge by incorporating it into the game and guiding players on a journey of developing that theme. It helps to add cuteness, relatability, humor, and surprise to keep the concepts interesting. Beyond tower defense games, Exploding Kittens is another great example of how game designers can take a creative license and build on existing notions of a theme.
In summary, carefully selecting a relatable theme and leveraging that theme for character development and game mechanics is an effective way of elevating the dynamics and aesthetics of a game.