Tower defense games started out as a mod for Warcraft 3 and have since become a vast genre that is represented on almost all gaming platforms. From Plants Versus Zombies to Defence Grid, there are as many different kinds of tower defense games as there are car crashes in Smallville. Independent developers in particular are having a ball when it comes to this genre and the latest indie tower defense game to hit the digital shelves is Sanctum.
Sanctum is a tower defense/ FPS hybrid where you play as Skye, an elite soldier who must defend her homeworld of Elysion One from hordes of alien attackers. Like most tower defense games, the story clearly isn’t the focus but the game does bring its setting to life by making the environments feel authentically alien, and what Sanctum lacks in story it makes up for in how solid the gameplay is. Most tower defense games follow roughly the same formula. What makes Sanctum different is that rather than organizing your defenses from an over the top view, you plan and construct your defenses in the first person. 
The game is structured into two phases. In the Building Phase you traverse the different alien environments and build up blocks and towers in order to defend your Power Core. You can build structures ranging from rapid-fire close-range towers, to higher damage, slower firing towers. These different towers aren’t all that new and original to tower defense games but where Sanctum does innovate is in the introduction of the "Televator". This acts as both an elevator for you to reach the higher levels of your defenses and a possible destination that Skye can teleport to. While it’s not the biggest innovation the genre has seen, it’s nice to see that Coffee Stain Studio’s is making an effort to differentiate Sanctum from the hordes of other similar games. Players are able to place towers on a grid based network which is fairly standard, but once again Coffee Stain Studios innovates by allowing you to place towers in ways that dynamically change the routes that enemies take when they attack your defenses.
The second phase of Sanctum is the Extermination Phase. In this phase, you control Skye and help your towers fend off the hordes of enemies that descend upon your defenses. You are able to directly help your defenses by using the handheld weapons that Skye has at her disposal. They are limited to just a rapid fire assault rifle type weapon, a sniper rifle, and a special beam weapon that can either be used to deal damage over time or slow enemies down.
Sanctum deserves special mention for the sheer variety in the different types of enemies that you have to defend against. The different types of enemies all have to be approached using different weapons, strategies and styles of play. Some enemies take more damage from rapid fire weapons and others have specific weakspots that must be exploited. In fact the style of shooter gameplay in Sanctum is very similar to Borderlands.
The style of shooting isn’t the only thing that Sanctum shares with Gearbox’s 2009 hit Borderlands. It also has the unique not quite cell shaded look that Borderlands had. This unique art style brings the games setting to life and actually gives a feeling of immersion, something that tower defense games are not usually known for.
Another difference that Sanctum has that separates it from other tower defense games is that it utilizes an interface that is very different to the conventional tower defense game interface. Since you play the game in the first person perspective, you target where you want to build your towers with your mouse and then you select your choice of tower by scrolling the mouse wheel. Following that you left click to build and upgrade towers and right click to sell towers.
While Sanctum can be a lot of fun, it’s unfortunate that it does lack map variety. The game features only three maps and while they are all fairly distinct it’s a shame that it offers less maps than a Call of Duty map pack. It’s good that Coffee Stain Studios have chosen to implement two player co-op, because this option adds a lot more re-playability to the three maps.
Sanctum is a game that pleasantly surprised me. Coffee Stain Studios came out of nowhere with this unique title that innovates in a lot of ways that other developers don’t bother with. Sanctum proves that while the tower defense genre is one of the most popular genres there is still plenty of room for innovation. For the $15 dollars that it costs on Steam, Sanctum is well worth checking out.