Every once in a while it is nice to take a break from a “real” (or “big”) game and play a “casual” game. Casual games bear much the same relation to big games as short stories do to novels – similar in form, yet with distinct rules and conventions.
Perhaps the biggest difference between the two lies in scope. Big games can go sprawling over large areas and long periods of time, involving many different actors and game mechanics. They expect the player will be at them for long stretches. Casual games are all about the three unities: time, space and action. The specialize in compact areas, short periods of time, few actors and straightforward game mechanics.
One of the more popular forms of casual game is the tower defense genre. The basic idea is that the computer sends wave after wave of units from off-screen marching toward a particular area (perhaps a castle situated on the bottom of the screen). The player's job is to defend that area by placing buildings (“towers”) that shoot at the computer's units. The units shoot the towers and are destroyed in turn, the player gets to build more towers and new units keep coming, and the whole thing is fun in a sort of “zombie apocalypse” way.
“Defenders of Ardania” (DoA) is an attempt to upgrade the tower defense genre by adding a few new wrinkles to this scenario. The underlying idea seems to be that tower defense games are really not all that different from real time strategy (RTS) games. Both of them have units and buildings and resources to build them both, so adding a few tools from the RTS toolbox to a tower defense game should improve it.
The first big change is that the player now gets to send units, too. Now you no longer have to just sit back and take whatever the computer dishes out, you can create units on your own! This is the biggest change in the genre that DoA implements. It changes the entire feel of the game from a simple “defend the castle”, passive struggle to a more back-and-forth battle for land and tactical advantage.
The second addition is unit experience. If you build a bunch of, say, wizards, then the wizard class gains experience points. After a while your wizards will be tougher and you can gain access to a “hero” wizard who is tougher still. This allows the player to mold their army to fit their play style.
The third addition is a magic system. The player can cast spells that have a direct effect on the game, rather than just creating units and buildings. This gives a feeling of more direct control over the action. Otherwise it can feel like the game is playing itself as your units and towers generally act on their own, marching toward the enemy or shooting at them without any input from you.
Fourth is the idea of different races. There are Human, Nature and Underworld sides, each of which has its own units, buildings and spells with their own strengths and weaknesses. This provides some variety for multi-player.
Last but not least, you can upgrade your base over time and gain extra bonuses of various types.
It is easy to see what developer “Most Wanted Entertainment” is working toward – a blend of the best of tower defense games and RTS features. They even received the “Most Innovative” award at E3 2011 from RTSGuru. The real question is, can they take all these different elements and make a good game out of it? The biggest hurdle will be making it simple enough to keep the flavor of tower defense games, while adding enough extra features and strategic depth to appeal to the RTS crowd.