The tower defense game is not a genre that is often given much attention in the critical discussion of video games. Usually light on the narrative qualities that game critics enjoy focusing on and often assumed to be a slightly more casual genre, there's still a lot to be considered in this type of game's appeal and in its most successful examples.

Our discussion, of course, touches on Plants Vs. Zombies, but we also look at a few other fresher titles like Anomaly: Warzone Earth and Defense Grid: the Awakening.