Metal Slug 3 really isn't the most complicated of games, especially when compared to what's currently on the market. Meant primarily as an arcade shooter,
Metal Slug 3 promotes non-stop action over things like plot and depth. Thumbing through the first few pages of the manual does, however, produce a long-winded story about alien invasions and stuff -- but I never saw much of a need for it. It's basically there as background fluff and an attempt to give you some legitimate reason for running around and shooting hordes of enemies -- like I really need one.
As already stated, the main gist of the game is to choose one of four characters and plow though a traditional 2D shooter. Think Contra only with more enemies. There's no real difference between the characters other than aesthetics, so choice isn't crucial to the process. As you go through the game's levels, you'll encounter soldiers, helicopters and tanks as well as some more outrageous enemies like mutant crabs and space aliens. You'll even encounter zombies who will turn you into one of their own (unless you find a cure or die -- whichever comes first).
Central to the game are the Slugs, which are machines that you can use to help ramp up the carnage. Slugs come in the form of tanks, planes, a robot suit and even an elephant. Although they bring a tremendous amount of firepower with them, Slugs aren't the most durable of things and will eventually blow-up.
Also scattered throughout the game are bearded POWs. Rescuing these downtrodden souls nets you weapon power-ups like the heavy machine gun, shotgun and rocket launcher. You can also rescue animals, like machine-gun toting monkeys and camels with rocket-launchers strapped to their backs to help you out. As if those weren't enough back up, you can even rescue lawyers (at least I think they were lawyers) who will summon a small rain cloud to zap enemies with a bolt of lighting. Hey, I never said the game took anything seriously.
The only thing better than playing through the game with gun wielding monkeys and lawyers is playing with a friend. Metal Slug 3 supports a 2-Player Co-op mode that is a blast to play through. Though the game sports the nice, shiny orange 'Live Enabled' marker, the online mode is only limited to an online scoreboard. This is a bit of a disappointment, but what can you do? Also included are two additional play modes that must be unlocked by completing the game: Fat Island and Storming the UFO Mother Ship.
Fat Island is a very unique 2-Player mode where you and a friend start at a certain weight. Every time you kill an enemy, food will drop. Picking up the food makes your character gain weight and turn into a fat blob (literally) - thus the point of the game. The trick is that the more weight you gain, the slower your character gets. This is where most of the strategy comes in since you have to learn how to best use the level to get more enemies (and food) to come to you.
Storming the UFO Mother Ship puts you in the boots of the Morden's soldiers (the guys you've been shooting at all along) as they try to overtake the UFO Mother Ship. You have a small group of soldiers and must progress though the level. As your army ventures deeper into the ship, you'll have to rescue comrades, increasing the size of your army.