Much like its predecessor, geoDefense Swarm by Critical Thought Games is not an easy game to master, but manages to remain a fun and visually exciting game that deserves its place amongst the best in the considerably well filled tower defense genre.

The addition of open field tower defense gameplay required some changes from the original geoDefense and what was once a fairly free-form placement of towers is now locked in to a hexagonal grid. Placement is fairly easy with a cross-hair placed above your finger as you drag towers to a precise location, though in the heat of the moment it is possible to drag the wrong tower and not know it till it's placed down.

Just like geoDefense the graphics are a visual explosion that use neon highlighted world objects and colorful special effects to push the limits of your iPhone. The earlier levels attempt to teach players how to play, though they're more for people already familiar with the genre. New players who manage to survive will soon come to learn they've not mastered the tricks of the genre, so it's fairly unfriendly in that regard.

Fans of tower defense games should consider adding this to the top of their collection and may even bump the original game if they favor the open field gameplay style. Newcomers to the genre might opt for a friendlier entry option, but there's enough leniency to learn the game then go back and get the high-scores.