Mercenaries is, generally, pretty forgiving in nature. The auto-aim function allows for a pretty wide margin of error, and you'll often find a convenient crate full of health and ammo when you need it the most. The AI in the game, both friendly and hostile, isn't incredibly cunning, but it's aggressive, and it's smart enough to run away from live grenades and to man nearby vehicles rather than stay on foot. Neither side is an incredible shot with a rifle, but it doesn't really need to be when it's coming at you with a rocket-propelled grenade or a heavily armored tank. When Mercenaries wants to present you with a challenge--and it will--it will simply throw an overwhelming number of enemies at you from a well-fortified position.
Only by taking jobs with multiple factions will you collect the intel you need to capture or kill the Deck of 52.
Though collecting bounties and gathering intel from the various factions are your primary objectives, there are plenty of side jobs you can take at will, and these range from simple checkpoint races to escorting a news reporter to an especially intense firefight. There are also standing offers that can help you curry favor with different factions. For example, the Chinese don't like the "listening posts" that the South Koreans have planted all over the place, and will reward you for destroying these surveillance devices. The South Koreans themselves don't much care for the presence of the large, aggrandizing statues of General Song that punctuate the landscape, and are made happier when you blow them up. The pacing of Mercenaries is relentless, and this is largely due to the incredible volume and variety of tasks you can take on.
Mercenaries puts a lot of stock in smoke, fire, and explosive effects, and these elements tend to dominate the screen for most of the game, which is great, because they're executed with incredible aptitude. The sky is almost constantly choked with a smoky haze, and the landscape is fundamental in giving you a sense of this war-torn country, but the game avoids becoming monotonous by providing subtle variations on this theme in different regions of the map. Part of what makes Mercenaries so engaging is the seamlessness of the landscape, and the fact that the game keeps load times to an absolute minimum--basically, the only times you'll see loading screens are before and after assignments, and when you die. But it doesn't sacrifice the quality of the graphics for scope, and all the characters and vehicles have a good look to them that, like the story, aims just to the more dramatic side of realism. There are some awkward pieces, such as the canned animations for when you subdue an enemy and your silly-looking jump animation. They're distractions, but they're usually overwhelmed by the game's grossly over-the-top action.
The visual quality of the game, along with the load times, account for the only significant differences between the Xbox and PlayStation 2 versions of Mercenaries. The game pushes the PlayStation 2 hardware pretty hard, and it gets a lot out of Sony's aging platform in the process, but the Xbox simply handles the load better. We noticed shorter load times, a better draw distance (though this is really apparent only when you're in a chopper), cleaner textures, a higher, more stable frame rate, nicer special effects, and slightly better animation. Not to marginalize the PlayStation 2 version, which is still a ton of fun and completely playable, but those with the ability should unquestionably go for the Xbox version.
Outrageous physics plus convincing smoke and fire effects make for some spectacular explosions.
There's virtually no difference in the quality of the sound in the two versions of Mercenaries, which is good. The voice cast of Mercenaries is the backbone of the game's sound design, delivering solid, believable performances that fit snugly into the characters. The best performances, though, come from Peter Stormare (the wood-chipper guy from Fargo and nihilist from The Big Lebowski), who plays the gravelly-voiced Swedish agent to a T, and from Carl Weathers (aka Apollo Creed and Action Jackson), who was born to play the part of the tough-as-nails Army commander that he voices here. The game is good about creating atmosphere with ambient sound, though when it really wants to get your blood up it'll kick in with a powerful, urgent orchestral score, a haunting choir of voices, or the driving sounds of big Asian drums. The quality of the sound isn't this great across the board, though. Some of the weapon reports feel a little flat, many of the engine effects don't sound as throaty as they ought to, and tires will often squeal even when you're rolling across dirt roads.
Mercenaries is dense with explosive content that satisfies on a fundamental level. Of the games that have tried to borrow the Grand Theft Auto style of play, Mercenaries is one of the most successful. This is partially because Pandemic clearly understands the importance of peripheral action to creating a cohesive, believable world, but also because it infuses the structure with its own style, and in the process turns it into something of its own. This is the most accomplished game that Pandemic has created yet, and it's an engaging experience that should appeal to action fans looking for a good, messy thrill.