I bought TF2 through Steam.
The classes are VERY fun. I'll just give a list of classes and their abilities.
Their name pretty much says it all. They get a rifle that zooms and it powers up the shot the longer you are zoomed in. Unfortunately, while zoomed, your sight is limited since you're looking in to the scope. Shoot people in to head to land a critical shot. Be careful, though, as enemies are able to see the dot which is projected from your rifle and can therefore attempt to elude you. The dot also gets brighter the long you're zoomed in, illustrating the fact that you're building up power by increasing the color of the dot.
They also have an SMG as a way of dealing with stuff that is at close/medium range. Their melee weapon is a kukri.
These guys are really fun. The weapons they start out are a flamethrower, shotgun and a fire axe. One of your jobs is to check for the another class (the Spy) which disguises itself as members of your teams so that they are able to move behind enemy lines. To do this you simply fire off your flamethrower and if the target ignites [when you ignite someone they take damage over time from burning] then you know that they are a Spy and that you should kill them!
The Pyro is also one of the classes that has been updated. Their base flamethrower has the secondary ability to fire an air compress blast. The blast has the ability to deflect or even reflect rockets/grenades/sticky bombs back at the person who fired them at you!
They get a flare gun that replaces their shotgun, too. It fires off a flare that does more damage the further it goes and it also ignites your target on fire.
The normal axe is replaced by the Axtinguisher, which does the lowest damage in game for a melee weapon and it cannot crit under normal circumstances. However, if your target is on fire while you attack them with the Axtinguisher you will ALWAYS crit.
They also get a replacement to the flamethrower called the Backburner. The Backburner does not have a compression blast, so you won't be able to deflect or reflect rockets. It also does not critically hit under normal circumstances, however, if you are able to catch your target from behind it will do critical damage every time.
The Pyro is also the only class that seems to have a "damage reduction" as they ultimately take less damage from other Pyros due to their flame resistance suit that they wear. Basically it just prevents them from burning for long periods of time.
Spies are the espionage class in the game. They have the innate ability to activate a cloaking device which renders them invisible shortly after you toggle it. While invisible you are unable to attack, you can still be attacked and players of the opposing team are able to run in to you and you are able to move. The cloak also has a gauge that starts at full and then slowly empties as you use it. This energy can be replaced by picking up ammo or by letting it rebuild itself over time. You are also able to disguise while cloaked, so that you can disguise, cloak, move behind enemy lines to backstab someone and then slip back in to the shadows after the task is done.
Their weapons are a pearl handled revolver, a knife and sapper. They also have a disguise kit that allows you to disguise as members of the opposing team OR members of your own team.
The knife is unable to critically hit from the front, however, a backstab will kill -any- class with a single shot; this includes a Heavy/Medic combo where the heavy has 450 HP.
The revolver is a highly accurate gun that allows for sniping with a skilled user.
The sapper is placed on Engineer buildings/sentry guns. It deactivates them and does damage over time until they explode. Sappers are destroyed when an Engineer hits the "sapped" building twice with their wrench.
It should also be noted that when you disguise as an enemy you assume their movement speed, so long as it isn't faster than your base speed. If you disguise as a Heavy you're going to move as slowly as they do, but if you disguise as a Scout then you'll keep the Spy's default movement speed.
I think that this is a great class to play for people with really high pings since you are able to make a sentry gun which attacks for you and I believe it isn't affected by ping. I'm sure a few Vogonites will be able to appreciate this.
As an Engineer you have the ability to create objects which greatly benefit your team members in a number of ways, however, they all take a resource known as metal. Metal can be obtained from dispensers [an object which you are able to create], the weaponry of fallen allies/enemies and from ammo boxes. Metal is useful in upgrading your creations to the maximum level which is three for all devices. You apply metal by hitting your buildings with your wrench.
The sentry gun is a stationary device that fires off bullets [at the first level] and gets deadlier and more health with each rank. The secondary rank increases the rate of fire and the third rank adds a rocket launcher that fires off a cluster of rockets. The ammo for the gun is replaced by hitting it with your wrench, but this comes at the cost of metal, as does healing the sentry gun with your wrench to heal it.
You are also able to make teleporter that is capable of quickly moving your teammates from the spawn point to the front lines. There are two parts of this device: the entrance and the exit. Upgrading one will upgrade the other, so you can build one next to your base and run back and forth replenishing your metal to quickly upgrade the entrance. The teleporters have a "recharge" time after they move someone which decreases with higher levels.
Dispensers are a great creation. Not only do they dispense metal for you to use but they also replenish health and ammo so long as the person using it stands close to the device. Higher levels dispense more metal/health.
You also have the ability to destroy any structure you've created by using a remote controller.
On top of all of this you also have a shotgun and pistol. Your wrench can be useful to smack people, too!
These guys just received an update so a lot of players are/were toying around with them.
The Scout is the fastest class in the game. They have the ability to double jump and when they capture points they count as two people rather than one.
Combat as the Scout generally involves utilizing your speed/leaping to your advantage.
As a Scout you are equipped with a scattergun, baseball bat and a pistol. Your scattergun is deadly at close range as it is essentially a more powerful shotgun while the pistol is fairly accurate damage for picking off long range targets. Your bat is your melee weapon.
Scouts received three new weapons with their update: the Force-A-Nature, Bonk! Atomic Punch and The Sandman.
The Force-A-Nature enables a third "jump", which is executed while the Scout is in the air and then fires the Force-A-Nature. The gun also knocks back targets that you shoot it with and it fires more "bullets" than the base scattergun along with firing its rounds faster. However, the Force-A-Nature only holds two rounds [down from the six that the scattergun holds.]
Bonk! Atomic Punch replaces your pistol and it allows the user to consume the energy drink to prevent damage for a shot amount of time. While using Bonk! you are unable to attack, however, everything will simply "miss" you. I've done some testing with a friend and it appears the only thing that can harm you while you use Bonk! would be being on fire BEFORE you use Bonk!. I'm not sure if fatal leaps or end of the level explosions at the end of certain maps kill you. When Bonk! wears off you are left with a debuffed speed.
The Sandman is a really cool toy. It comes with the bat [of course] and a baseball. You only have one ball but it will "replenish" over time. Alternatively you can simply pick the ball back up after you've used it. The ball has the ability to stun anyone [except for players using Bonk!, I think] -- this includes people under the effects of an Ubercharge -- for a duration based on the distance the ball traveled before hitting the person. You are also able to melee with just the bat, whether the ball is currently held or not, if you target is at extremely close range. However, The Sandman disables your double jump feature. You're still able to use the Force-A-Nature for the extra jump, though.
Balls from other Scouts can be used against them as long as the player has The Sandman equipped. Basically if you fire off your ball and the other Scout fires their ball and it lands near you, but doesn't hit you, you'll be able to whack it back at them.
These guys are slow moving and durable targets. They have the ability to rocket jump by firing a rocket at the ground as you jump to ascend to high places quickly. It is also useful for getting airborne to rain down rocket death upon your enemies, too.
Your weapons are a rocket launcher, a shotgun and a shovel.
These guys are the tank of the game. They have the highest base HP in the game. Their weapons are a minigun, shotgun and their fists as the default weapons.
You are able to "spin down" the minigun to prepare yourself for approaching enemies, but doing so will further lower your speed. If you crouch while spinning your minigun you will be unable to move at all.
The Heavy class has also received an update. In this update they obtained Natascha, Sandvich and K.G.B..
Natascha is the minigun replacement and it fires off rounds that actually slow your enemies when they're hit. However, Natascha does -25% damage per round to compensate for having a slow.
The Sandvich replaces your shotgun and you are able to eat it to restore lost health. Doing so is VERY loud and you are unable to protect yourself as you eat. This item has unlimited uses, though.
The K.G.B. is the replacement to your fists. These boxing gloves swing 20% slower than your fists do, however, a kill with the gloves on gives you 5 seconds of critical hits; anything you fire [be it more punches, shotgun or miniguns] will automatically crit. This buff can be extended by racking up more kills with the gloves.
The Demoman is great at blowing things [be it people or devices] to pieces. His guns consists of a grenade launcher, a stickybomb launcher and a bottle.
The grenade launcher has four rounds and the shots will bounce off of walls or ceilings. They denote a short time after they're fired or if they hit an opponent. If a grenade is on the floor don't assume that just because an enemy walked over it that it will explode.
The stickybomb launcher is great. You have the ability to place up to eight stickybombs on walls, ceilings and the ground. They don't denote until you tell them to explode, too, although enemies can "shoot" them to destroy them. Stickybombs are also destroyed when you die.
The bottle is just your typical melee weapon.
The Medic is tasked with healing teammates and buffing them up to prevent them from dying. This does not mean that he is unable to protect himself in one on one combat.
The Medic heals damage over time on himself and the amount of damage healed is based on how low your health is. The more time you spend healing the larger the "ticks" of health will be.
The basic weapons for the Medic are the Medigun, a syringe gun and a bonesaw.
The syringe gun is basically a machine gun that fires at an arc.
The bonesaw is your basic melee weapon.
The Medigun heals allies [or enemy Spies!] and allows you to buff them to 150% their normal HP. As you heal players you will build up your "Ubercharge" which allows you to make yourself and the target of your Medigun invulnerable for a short amount of time. Your Ubercharge MUST be at 100% to activate this, though.
The Medic has also receive an update. The replacement weapons are The Kritzkrieg, Blutsauger and Ubersaw.
The Kritzkrieg charges 25% faster than the Medigun and also allows you heal/buff your target to 150% of their normal HP. However, instead of making your target invulnerable, it gives them automatic critical hits for the next 8 seconds.
The Blutsauger replaces your syringe gun. It is unable to critically hit but each "round" that lands will heal you for +3 HP.
The Ubersaw swings 20% slower than the bonesaw but each hit gives you +25% towards your Ubercharge, be it the Kritzkrieg or Medigun.
I hope this information is helpful to anyone looking at the game. I think that you need Steam to play the game, though, but downloading Steam is free.