Team Fortress 2/Heavy

The Heavy is the strongest class in the game, with 300 health, but also the slowest. He works best at medium or short ranges, and best in defence due to his speed, but with a Medic can good at offense too. They carry:

Minigun (weapon 1): The minigun is powerful, capable of spraying bullets at high speed, causing a large amount of damage. It's incredibly powerful against the lighter classes such as Scouts (with a good amount of aiming), Medics, Engineers and Demomen, and even the Soldier, given that the Heavy can soak up damage from Soldier rockets quite easily (providing it's not a critical). It also does not need reloading, meaning you are able to rampage the enemy face on, destroying everything in your path. This, however, means that the minigun chews up ammo very fast and you will often find you have run out of ammo very quickly. Another disadvantage is that you are incredibly slow when firing, leaving you vulnerable to a Spy or Sniper. This weapon needs a few seconds to wind up and lower into position before it actually starts firing, although pressing the right mouse button allows you to keep it spinning, but at the cost of your speed. Whilst spinning the minigun, you cannot jump, and if you crouch you cannot move.

Shotgun (weapon 2): The shotgun is only really useful when the Heavy needs a slightly more accurate weapon or has run out of ammo for the minigun. It can be slow to reload but can be a very effective weapon at close range, or at greater ranges, since there is a certain degree of luck involved with the minigun at further ranges as to whether the bullets are going to hit or not.

Fists (weapon 3): The Heavy bare fists are used to humiliate more than anything else, serving as the Heavy's melee weapon. Interestingly, the left mouse button punches with the left hand, and the right mouse button punches with the right hand.

Using the Heavy
The Heavy is very useful in defence, but even without the backup of a Medic can still be a formidable offensive force (providing there are no skilled Snipers or Spies around). If you get a Medic healing you and he has an Ubercharge, you're pretty much set to cause carnage, so just rush straight for the enemy. Whilst Ubercharged, destroy any sentries first - otherwise, pick a target and get as close as possible to them whilst firing the minigun. Once they're dead, move on to the next target - and so on.

The Heavy isn't really an ambush class, but beware of Snipers when using one out in the open. Just run to where the action is and pull out your minigun aiming for everything that moves. Becareful about fighting Soldiers or Heavys with Medics, as they usually kill you before you can kill them. Another thing to look out for is Spies, as they can backstab you quicker than you can turn around. Make sure you call out Medic when one is near, so that they will concentrate your healing on you.

Make sure you also go for any ammo boxes or weapons on the floor, as the Heavy uses ammo at an alarming rate. Alternatively, defending teams can use Dispensers to fire the minigun continuously, never running out of ammo (providing you stay near the Dispenser - this also applies to the Pyro, but the range of the flamethrower means that this is only really good for eliminating Spies).