The Heavy and the Strength Power-Up go make a simple, understandable combo.

It should be obvious to anyone that a Heavy and a Power-Up that boosts his damage makes for a fierce opponent. Only a few other classes like the Sniper and Pyro can use this Power-Up as well as the Heavy. This goes well with any minigun, potentially halving the time it takes to kill a foe with focused fire. It also goes great with the Family Business by getting rid of the damage penalty. Another combo you might aim for is the Steak Sandvich and Bear Claws. It basically turns Heavy into a killing machine who uses Melee only, but in tight areas, an extremely effective killer at that.

This one's a bit tricky, but the Haste Power-Up is one of the best offensive tools for the Heavy.

Haste increases mobility slightly and doubles your ammo capacity. The movement speed is as nice as it is expected, and makes the Heavy slightly faster to counteract one of his weaknesses. Heavy's other weakness is his low ammo capacity, which is doubled. On top of this, Haste increases weapon firing speed! This also increases Heavy's damage output by a ridiculous amount, allowing him to kill enemies very quickly if he keeps focus on them, and also makes his Minigun's rev-up time faster.

Need I say more?

The Heavy becomes 50% more resistance to ALL damage sources AND gets crit immunity. This means no extra damage from Guillotines while stunned, no extra damage from Back Burner, and no headshot crits. It emphasizes what the Heavy was made for - Bulk. Your only weakness is probably knockback from Sentries and Stickies, and Spies. Watch your back or else you'll lose a very valuable powerup!

In my experience, the best Power-Up for the Heavy is the Vampire Power-Up.

Resistance is all well-and-dandy with damage reduction and crit immunity, but it won't let the Heavy survive against the entire enemy team. What will? The Vampire Power-Up, of course! As long as you don't get backstabbed and keep your fire on an enemy, you can probably just sit in the middle of the map and fight the whole enemy team. What's even better? Damage resistance, extra health, and the fact that not just a bit of damage is given to you as health, but 100% of it! Be warned, this does NOT work on buildings.

Ever been frustrated by NOT being able to shoot that Sniper to death with your Minigun?

Well now you can! Basically, Precision turns weapons like the Shotgun, Scattergun, and Minigun into Sniper Rifles and Laser Beams! This upgrade covers another of the Heavy's major flaws, the ability to hit literally nothing far away! I've killed tons of Snipers who have had it out for my tiny head with this Power-Up, and it also works well with Rocket-Jumpers and allows you to pick off other close-ranged classes like Pyros and other Heavies before they can get in range of you. I use it for taking down Sentries most of the time, and their Engies too.

Whoosh!

This covers all of Heavy's problems regarding movement. Extra grapple speed, fast weapon switch, movement speed, and jump height all in one package. Basically it turns the Heavy into a wannabe-Scout, and it makes him MUCH more capable of just about everything. It allows you to escape harassing classes very easily so long as you know how to use your grapple and environment to your advantage. Sadly, that's about it. The only other bonus I've seen for the Heavy with this Power-Up is the fact it makes him a good Intel theif.

Aim for the Sandvich, Engie!

This is probably THE best Power-Up for the Heavy. The best part is that you don't have to pay any attention to it. It's entirely passive and you can play just like you normally would. Regeneration gives Heavy a constant flow of Health and Ammo. However, Valve saw this coming and decided that the more Health a class has, the slower HP regeneration should be. But that's fair. Heavy with extra ammo and health regeneration should make him quite the tank - And it does, but Medic is probably better suited for this option. Pyro argueabley makes the best use of this Power-Up.

Vhen little baby hurt Heavy, little baby get hurt from fear of vhat vill happen next.

Extra Health, and 50% of damage taken is returned. This is an amazing Power-Up for the Heavy, as it makes use of his large Health stat and even buffs it up to 450 (However upon picking this Power-Up off the ground, you must find a Medic of Health Kit to heal up to your maximum of 450). The only downside is that you can't directly kill enemies with returned damage, but with a Minigun that will hit everything you aim it at at least once, you should be able to pick off Scouts that are harassing you like flies. It also makes Spies fear back-stabbing you, since they'll be knocked down to 1 Health. This Power-Up combines Offense and Defensive roles and makes the Heavy a tricky foe to take down.

Cry some moar, babies!

Iz too late. Babies are dead, and cannot cry. The Critz Power-Up is the only temporary Power-Up, but with way too good of a reason. When I say, "Temporary", what I mean is more than enough time to kill the entire enemy team if they all happen to cross your path. This Power-Up gives you 30 pure, unadulterated seconds of full-power Crits. Not mini-Crits, but the real deal. It's pretty much like winning a round and going in to kill off the last defenseless members of the enemy team, only they might scratch you up a little before you get 'em all. Well, that's it. An amazing Power-Up that only gives Heavy cri- -Wait. That's not all.

On top of EVERYTHING above, the real seller for this Power-Up is the fact it's not a Power-Up at all. It's almost like an instant Crit Canteen. How is this a good thing, you ask? Well, because you can use ANOTHER Power-Up while being Crit-Boosted! Precision Heavy can snipe enemies dead in seconds, Vampire Heavy can suck every last drop of life from the enemey team, Haste Heavy gets the highest DPS in the game, and Agility Heavy runs around like a mad psycho! There's nothing bad about this Power-Up, and I believe the Heavy with any other Power-Up combined with Crits should instantly be deemed the most powerful part of your - Or the enemy's - Team.