Pluto Attacks plays much like a game from the long-running Worms franchise, in which players control an anthropomorphic worm who then attacks other worms representing other players with projectile weapons. Here, you control tanks, moving across a widely different series of maps as you try to wipe out your opponents. Aiming is based on identifying a proper trajectory with the arrow keys and determining how effective the blast will be by clicking on a power meter at the bottom of the screen.

Once everything is in position, you let loose and watch your weapons rain down on your opponent. As you level, you'll also gain new weapons and special bonuses such as double attacks and the ability to repair yourself on the battlefield.

The good news is that all this is based in a multiplayer environment from the very beginning. Within only a few minutes of installing the game, you'll find yourself matched against another random player on one of the simplest maps (and you can unlock more as you level). Depending on how well you performed, you'll receive a varying amount of digital currency that you can then use to upgrade your tank's attributes or its cosmetic appearance.

Every match also provides you with at least one achievement-based mission (such as dealing more than 150 points of damage in a match), and matches eventually grow to include multiple players and different objectives. Pluto Attacks even allows for team-based battles, which makes this an entertaining title to play with your friends.

But if multiplayer isn't your thing, there's also a campaign that details Pluto Attacks's attempts at conquering Earth. Not only does it provide a story in the form of humorous interactions between Earth's defenders and the Plutonian invaders, but it also serves as an entertaining tutorial on how to perfect your combat skills and experiment some of the many different types of weapons available.

There are even a few bosses to experience, although few of these are particularly challenging if you understand the basic mechanics of the game. All in all, it's never quite as engaging as the multiplayer battles, but the option for a change of pace is a welcome one.

There's very little not to like here. Some players might balk at the inclusion of an energy bar that somewhat limits the time you can play and long waits for upgrades to vehicles, but neither really proves detrimental to the gaming experience. Pluto Attacks is what Facebook games should be like, and it provides a skillful combination of a likeable design aesthetic, intuitive menus and controls, and rewarding gameplay that remains entertaining long after you first experience it.