Heavy match-ups

From TF2 Wiki

Class			Threat	Strategy
Heavy	v	Scout	Low - Medium	Scouts pose little threat, beyond close range combat, and they'll often try to avoid you. However, be aware that, at close range, they can circle strafe very quickly. If you find yourself unable to keep your crosshair on him, consider turning in the opposite direction he's moving or standing still in order to catch him on his way around; if you do catch him, he'll likely die quickly from your Minigun, or simply flee when you don't play his game. At this point, ventilate his back to avoid him finding an alternate route to attack you. Trickier Scouts may land on your head, to maximize the damage they deal before you notice them, so remember to look up aswell.
Heavy	v	Soldier	Medium - High	A Soldier's rockets can spell hell for any Heavy. Once you spot a Soldier, put them down quickly. Due to the Heavy's slow speed, dodging rockets is difficult, but not impossible. Quickly un-deploying the Minigun and leaping in the air to one side can often minimize if not completely avoid the effects of an incoming rocket. You want to be get within medium range of the Soldier to take them down fast, but remember not to get too close as Heavies are easy targets for directs hits with the rocket launcher.
Heavy	v	Pyro	High	Pyros are one of the most dangerous things you will encounter as a Heavy. If a Pyro comes at you from behind with this weapon, you will have around one second to spin around and take him out. If multiple Pyros attack at once, simply try to take down the closest one before they can get in range. A high mouse sensitivity is a must when dealing with Pyros as they will try to circle-strafe you, as well as dodging erraticly when approaching from head-on. If you are ambushed by multiple Pyros, unfortunately your chances of survival are almost non-existant. Pyros using the Flamethrower are less of a threat, especially from behind. If they use their Compressed Air blast on you, this will simply push you out of range of their Flamethrower long enough to spin up your Minigun.
Heavy	v	Demoman	Medium	An undeterred Demoman can take you out swiftly with a volley from his Grenade Launcher (it's not hard to rapidly score four direct hits on a slow-moving Heavy). Your best bet is to send some bullets his way, to force him into cover, where he'll probably try a less efficient indirect attack. At this stage you will want to close the gap between you and the Demoman as soon as possible. Charge to his position, leap towards him and deploy your Minigun. He will die very quickly. Avoid walking over sticky bomb carpets, as your slow speed makes you a very vulnerable target for these. Even when paired with a Medic, a cluster of stickies will either take you out in one hit or severely damage you. Instead, if you have ammo to spare, you can use your Minigun fire to push them out the way. Make sure to move on through before he catches on and resets his bombs.
Heavy	v	Heavy	Medium	Other Heavies can go down surprisingly quickly provided you: A. have more health, or a Medic healing you, B. spin up before he does (remember that your alternate fire keeps your Minigun spinning) or C. can surprise him. Having more ammo also helps. Remember that if one Heavy starts firing criticals, they will almost always win the encounter. Try to get behind cover if you hear the tell-tale sound of an enemy Heavy's criticals. It is very possible to take down an enemy Heavy paired with a Medic (even if you do not have one yourself) at close range by simply being the first to fire, since you will be doing hundreds of damage per second you can damage him faster than his Medic can heal.
Heavy	v	Engineer	Medium	A low level Sentry is a minor threat; the Heavy can take it down easily with sustained fire. If he has good cover and a Medic behind him, a Heavy can also take out a level two or fully upgraded Sentry. If it is accompanied by an Engineer, simply shooting at it will not suffice. Try to take out the Engineer and then the Sentry. Alternatively, activate your ÜberCharge to get close to the Sentry and destroy both it and the Engineer, allowing your team-mates to rush through. As with most UberCharges, it is important that the Medic runs out ahead in order to distract the sentry, this will allow you to get as close as possible in order to take it down. Remember that when crouching, the Heavy is harder to knock back, use this to your advantage to avoid the push-back effect of sentries. When facing a lone engineer, you should have no problems as you will be able to cut through him like butter, even at long range.
Heavy	v	Medic	Low	Medics pose very little threat to a Heavy unless they are using their ÜberCharge on an enemy team member. Although Medics tend to shoot you from afar with the Syringe Gun, it shouldn't pose much of a threat to a Heavy. Watch out for 'hero' medics who may try to take you out with their Uber/Bonesaw after you have taken down their patient. Due to the range of the Medic's melee weapon, using your fists is rarely a viable option in this case. Cut him down.
Heavy	v	Sniper	Very High	The most dangerous thing you will face. This is truly your worst nightmare. At long range, a Sniper's fully-powered headshot will kill you even if a Medic has powered you up to 150% health. Your slow speed makes for an extremely easy target, so avoid Snipers at all costs. You will not be able to dodge a good Sniper, it is simply not possible. Their threat of course diminishes as you close in on them. You can also use sustained fire on their position to keep them in hiding as you approach, but be aware that this will not work on an experienced Sniper, as if you can see him, you will be dead before you can begin to spin up your Minigun. A Sniper at medium to close range is very little threat; simply mow them down.
Heavy	v	Spy	Low - High	Another one-hit death to watch out for when playing a Heavy is the dreaded backstab. One of the tasks of an enemy Spy is to assassinate troublesome Heavy/Medic pairs. They are however, very easy to kill once you've caught them. You will want to Spy check very, very often if you can afford to. There is basically no such thing as Spy checking too often. Do not rely on your Medic to spot Spies for you, your job is to prevent them from backstabbing him. When on your own, you are an even more vulnerable target, so don't forget to stay alert for people behind you - all the time. If a Spy should cloak and run away, the spread of your Minigun fire should allow you to find him and mow him down. Try not to let him escape, because often he will sneakily return for another attempt. In close-quarters combat, avoid letting the spy get in your rear 180-degree arc where he can use his backstab. That strategy is risky for the spy as well: your minigun does significant damage at close range.