Just when I thought the last nugget of creativity had been squeezed out of the tower defense genre, a developer like 3 Sprockets comes along to prove me wrong. The developer released Cubemen a few weeks ago, which is a tower-defense game that eschews your standard immobile turrets for perfectly ambulatory men made of cubes. Aside from the ever-changing real-time-strategy dynamic this adds to the tested formula, the inclusion of head-to-head competitive gameplay modes make for some action-packed battles against other humans or computer AI.

Little cubemen of different colors just don't get along. It's an age-old truth, and really the only narrative underpinning you need to know to understand the action in Cubemen. Two primary game-types--Defense and Skirmish--are available, each with a few possible permutations. "Defense" mode is your classic tower defense setup, in which the player has to position his forces to defend his home base. "Skirmish" mode puts a base on each side of the map, creating a war of attrition between the two sides in a human vs. human or human vs. AI scenario.

Furthermore, each mode can be played in three flavors: Classic, Limited Players, or Limited Cubes. These rule subsets are just as they sound. Classic mode is restriction-free. Destroying enemies earns you cubes which can be spent to build and deploy new units. "Limited Players" restricts the total number of cubemen that can be deployed to the battlefield at a time, and "Limited Cubes" forces the player to build an army using a finite number of available cubes. Since each type of cubeman is armed differently--and has a different price--players have to be a lot more careful about how they spend their resources.

Cubemen has a robust variety of 3D maps of varying size, complexity, and difficulty, which helps keep the experience fresh from game to game. Classic tower defense games in Cubemen are fairly refreshing, given the player's ability to select any unit and direct it to another location at any time. As you'd expect, the Cubemen themselves come in a number of different varieties, ranging from the standard pea-shooters to those with mounted flamethrowers and freeze capabilities.

The game's head-to-head multiplayer mode is where Cubemen really shines, creating some truly intense battles. The AI is a more than competent opponent, but playing against another human being is the way to go. Smaller maps suffer from a bit of "out-click your opponent to win" syndrome, but larger, more complex maps give the proceedings more strategic options, given the number of additional positioning options for the cubemen. Cubemen's head-to-head mode is its most unique (and strongest) suit, and the ability to move individual units around makes the game bring to life the game's real-time-strategy and tactical puzzle elements. Matches can be fast and grueling, but are ultimately very fun and rewarding. If you're a tower defense fan, Cubemen is worth a look if for no other reason than to try out this mode.

Cubemen has a few shortcomings, namely in how it gets players up to speed. The tutorial is pretty sparse, covering basic mechanics, but not really delving into the strengths and weaknesses of the different unit types. The matches themselves are incredibly fast-paced, which makes learning the nuances of each type of cubeman a bit difficult in the heat of a match. It's a surmountable learning curve for self-motivated players, but one that's exasperated a bit by the similarity of each unit's visual presentation. Side by side, it's easy to tell units apart based on their size and equipped weaponry, but when the playing field becomes cluttered with units and activity, I longed for a more stark, visual contrast between units.

Nitpicks aside, Cubemen is a welcome addition to the tower defense genre that delivers a tense, competitive play mode that is well-worth experiencing. Best of all, the game is quite affordable, for those interested in checking it out. Cubemen is available for PC via Steam for $4.99, and for Mac and iPad 2 and later for $3.99 on iTunes and the Mac App Store.