If you've played Desktop Tower Defense, you already have a good idea of what to expect from PixelJunk Monsters. The goal of the game is to defeat successive waves of enemies by building a series of upgradeable towers. While the core gameplay remains the same in PixelJunk Monsters, it also adds a few new twists that help make the game even more addictive and enjoyable.

Although simple, PixelJunk Monster's visuals are clean, crisp and appealing. The art style has a basic look that is somewhere between watercolors and cel-shading. Lines are crisp and black, but the coloring has a blurry look. Everything has a unique look; your avatar looks like a hybrid of a tiki-god and a turtle, while the monsters range from small spiders to bats to big, burly, gorilla-like monsters. Best of all, even with dozens of cannons and monsters on the screen, there is never a hint of slowdown.

Sound is low-key, but in a relaxing way. Even as a group of 20+ monsters threaten to crush the citizens you are protecting, the background music is low and melodic. The only disappointing aspect is lack of sound effects; but even this isn't a major deal considering more effects could have ruined the atmosphere created by the music.

One of PixelJunk Monster's twists is your avatar, whom you must guide around the map in order to build towers. Construction is built around three main resources: trees, gold and gems. Trees act as sort of a template indicating where towers can be placed. As long as you have enough gold, which is earned by killing monsters, any tree can be converted into a tower. Once a tower is in place, it will automatically attack any monster that comes within range.

Towers come in a variety of types and can be upgraded either by having your avatar dance around them, or by spending gems to give them a quick boost. Most of the game's strategy revolves around choosing the best tower type for a particular situation. Basic towers can attack ground and air units, but do little damage. Gems can also be used to purchase new tower types and other upgrades, like specialized turrets that can quickly destroy one type of unit. These choices factor into the game's strategy since gems come in limited supply. Also adding to the strategy is the ability to destroy towers, which gives you back some of your investment. This allows you to quickly reinforce your main turret configuration while not being stuck with useless towers. You'll also have to decide whether to dance around a tower to upgrade it, or make a run across the screen for dropped coins. There's a lot going on here, which helps to bolster the game's addictive qualities.

After fighting off waves of enemies, you'll eventually have to take down a series of boss enemies that will really test your basic configuration. Boss monsters are generally harder to kill, and it is depressing to see your villagers get stomped in the last wave, but it's a great motivator.

Although it may sound complex, PixelJunk Monsters is very straightforward. You always know what group of monsters is coming next and are given plenty of time to prepare, so there are no "cheap" surprises. The introductory tutorial takes no time at all and gives you all of the basic information needed to jump right in and play. PixelJunk Monsters also does a great job at handling its difficulty curve. Rather than keep you on one set path, you are instead given a number of paths, each with its own difficulty. All of the paths lead to the same goal area; however, taking the path full of "Easy" battles also requires the longest travel path. You'll eventually want to conquer all of the areas, though it is nice to have the option.

Though it never gets "cheap", PixelJunk Monsters does get challenging in later stages. Though the mechanics are rather simple, there's a surprising amount of strategy at work as you scurry around trying to build, upgrade and destroy towers in anticipation of the next attack wave. Even when you do fail, the action is addictive enough that you'll quickly want to jump right back in and try one of the dozens of new strategies that pop into your head. A buddy can join you for a bit of two-player action, which reduces the difficulty as long as you are both on the same page strategically.

PixelJunk Monster's general interface uses a clean, icon-based look that is easy to understand. A gauge at the bottom of the screen lets you know what sort of monsters are coming next and how close they are to your base. Features like the strength of your towers are denoted by colored flags while each tower's experience total is shown as a red meter. Controls are just as simple to use; the analog stick or D-pad moves your avatar around the screen, while choices can be selected or deselected by pressing (X) and (O) respectively.

Another of the really cool options available in PixelJunk Monsters is remote play via the PSP. Provided both your PSP and PS3 have the required updates (which they more than likely should), you can run the game on your PS3 and play it in another room using your PSP. There's a slight bit of lag and the graphics take a bit of a hit, but the overall response is great.

PixelJunk Monsters is the type of game that services like PSN or XBLA were made for. It's a fun, simple experience at a cheap price - making it a must download for strategy fans or anyone looking for something a little different than the PS3's other offerings.