SourceOk, so I was going to have all of the pictures too, but Imageshack is sucking balls, and I'm not going to make a photobucket account just for this thread. Anyway, here they are:
Demoman: If you can't aim and you love big explosions, the Demoman was made for you. In an assault on a checkpoint, the Demoman is best as a support member, launching grenades from long range. Thanks to some of the great physics in TF2, truly skilled players will learn to bounce their grenades off walls and ceilings in order to hit targets while remaining behind cover.
The true effectiveness of the Demoman is in holding down areas. Sticky grenades can be laid out as thick as carpet around a base or checkpoint. Either the enemy will stumble into the glowing grenades or you can detonate manually. If you get creative, you can hide grenades in hard to spot places and give the opponent an explosive surprise.
Engineer: On the surface, the Engineer would seem like a boring class to play. After all, they are terrible combatants with weak short-range weapons at their disposal. But the Engineer turns out to be one of the most enjoyable classes to play in TF2.
As an Engineer you must think tactically, placing a turret, teleporter, or ammo dispenser in the most advantageous positions. The building of each device can be sped up by hammering the construct repeatedly with your wrench. Multiple Engineers assembling turrets together can prove incredibly effective. Turrets can be upgraded multiple times, evolving from standard machinegun to rocket launcher. Every enemy killed by your turret counts towards your stats, so while the Engineer is not much use in direct combat, you still enjoy the statistical spoils of war.
Heavy: Pretty much the coolest-looking character in TF2, the Heavy is the bad ass with the BFG. He's slow, but is the perfect choice for storming an enemy stronghold. At close range, the Heavy's minigun shreds through enemies. Granted, the Heavy will have a tough time avoiding incoming attacks. But the Heavy also has the most health of any class, making him an awesome weapon against the opposition.
The Heavy's nemesis class is the Sniper, for somewhat obvious reasons. If you leave the Heavy out in the open, even a poor excuse for a Sniper will have little trouble clipping him. Using an Engineer's teleporters, the Heavy can stay indoors and out of the sights of pesky Snipers. As long as you get the Heavy in close, the opposition stands little chance.
Medic: In most class-based games, the medic has tended to be the least interesting role to play. They throw out med packs and fire puny weapons and rarely share in the glory. Not so with TF2, where the Medic takes an active role in assisting teammates. To heal teammates, the Medic needs to shoot them. This fires a continuous stream of health at a locked-on teammate. As you heal teammates, a charge meter fills. Once it's topped off, the Medic can give temporary invulnerability to himself and a teammate.
Generally, the Medic is best when teamed with the Heavy. The Medic can stand around the corner (the beam can bend slightly) and keep the Heavy healed as he lays down a stream of bullets at the enemy. Once charged, the Heavy becomes invulnerable, making him the most potent weapon in TF2. Being a partner in a killing spree is just about equal to doing the damage yourself. Consider the Medic Bonnie to the Heavy's Clyde.
Pyro: This is a pyromaniac's love story. The Pyro is not the easiest class to play right off the bat. More than likely, the first time you take control of the Pyro, you'll misjudge the distance of the flamethrower and get a face full of bullets instead. The flame has a very small reach. In fact, it's so short, it might be considered an extended melee attack. But when a Pyro gets in close, it's pretty much an instant kill. Even if you only get an opponent in the path of your flames for a second, they will catch fire and burn. If they don't get to some water quickly, they'll be (burnt) toast.
The Pyro is the perfect class for sadistic gamers -- the kind who like to cackle every time they kill an opponent. Setting fire to the cartoony characters of Team Fortress 2 is one of the more satisfying experiences in Valve's new multiplayer title. But you have to smart about how you handle the Pyro, primarily due to the short range of his attacks.
Scout: The Scout is absolutely the most ridiculous character in TF2. He moves as fast as a roadrunner and has the benefit of a multi-directional double-jump. Though the Scout has very little health, he's the toughest class to hit in the open. Anyone who masters the double jump (which allows a mid-air directional change) is certain to give fits to the opponent. The Heavy, who moves at the pace of a slug, will be particularly vexed by the speedy Scout.
The Scout is the only class that should focus on melee attacks. Thanks to his speed, the Scout can quickly get behind enemies and crack them over the back of the head before they can turn. The Scout is particularly effective as an Infiltrator, running into the enemy base, dodging fire and causing mayhem. By that same token, the Scout can also be great for causing distractions. Use a Scout to draw the attention of enemies and have your Engineer sneak in and set up a turret while the opponent is occupied.
Sniper: The six maps included in TF2 were designed with all nine classes in mind. That means you can expect multiple sniping perches, making the sniper a valuable asset in every match. The Sniper's shot can be charged, so that a single shot (even if it misses the head) can prove lethal. The only trouble is that the fully-charged shot created a laser point visible to the enemy. It would seem this provides an unfair advantage to potential victims, since they will sometimes be warned of an impending snipe. In practice, however, the combat is so fast and furious in TF2 that a Sniper's targeting efforts aren't recognized until the bullet has already done its damage.
The only challenge in playing a Sniper that we experienced is that some maps feature extensive interior areas. As the Sniper is only truly effective shooting into open areas, there are times when the class becomes ineffective. But more daring Snipers can switch to the submachine gun when the action moves indoors. At close range, the SMG can do some serious damage.
Soldier: The Soldier is the perfect choice for the player who likes the idea of the Heavy but wants more mobility. With a powerful rocket launcher, the Soldier is deadly on the front lines. And thanks to the rocket jump (which is inspiring to perform), the Soldier can find entry points into enemy bases that are often poorly defended. If an enemy Sniper is in a window popping headshots into your friends, get the Soldier airborne and he can quickly deal with the menace.
The Soldier is the most comfortable of the classes, the one that is easiest to adopt. He's more or less your typical deathmatch character. And while the Soldier doesn't have the brute strength of the Heavy or the cool gadgets of the Engineer, he's a great default class.
Spy: There is no more interesting or complex class as the Spy. Though he's pretty much useless in direct combat, the Spy is a marvel to play. Using his disguise kit, the Spy can assume the identity of the opponent and will even have a mock user name to help fool the other side. The trick, however, is in learning how to assume the role properly. If you are pretending to be a Sniper, you'll want to find a perch and wait. Let the opponent be fooled into thinking you are actually a Sniper. Then, when no their backs are turned, pull out your knife and take them out.
The Spy's ultimate rouse is to fool an opposing Medic into healing him. Though you don't earn the powers or weapons of a class you're pretending to play, an opponents' medi-gun will still heal the Spy. You can even be turned invulnerable by the Medic. So if you play your role properly, you can trick a Medic into turning you invulnerable, then drop the disguise and gut everyone. When pulled off, it's a phenomenal sight.
It should be noted that your disguised Spy will appear, in every way, to be working for the opponent. As a Spy, any shots fired will look like shots from your assumed role. And if you hit a friend, though you won't actually do damage, it will appear to the enemy that you have. You don't have to worry about fooling your real friends, though. To your allies, the Spy looks like his regular self, but with a cardboard cut-out mask of his disguised role. And all the while he continues to smoke his thing cigarette. Brilliant.
