Pyro

Similarly to the Soldier, the Pyro is a jack of all trades that can perform several duties very well, but is usually never the best at any one role it's given. Pyro can clear up clusters of small robots or burn down a giant at point blank range, but is often dependent on the robots being distracted with something else. Outside of doing damage, Pyro can sometimes assist against giants with airblast***, but airblast is more often than not a double-edged sword and should only be used sparingly and in specific scenarios-- more on this later. Finally, Pyro is the most popular choice for busting tanks.

Pyro is a very common choice for newer players, but is actually surprisingly difficult due to its close range and limited survivability on the early waves-- assuming you choose not to equip a particular secondary weapon. If you're not already loaded up on resistances and/or have a pocket Medic, then playing Pyro will revolve around using flank routes and sticking close to corners and other sources of cover in order to minimize the amount of attention coming your way. You can quickly melt robots that you catch off guard, but if their focus turns to you, you can also be quickly destroyed. Pyro's general effectiveness tends to vary from map to map; it does very well on Mannhattan, but struggles on Coaltown.

Common mistakes

The general attitude surrounding knockback and Pyro in general might have you assume that airblasting is inherently bad-- strictly speaking, it isn't, but you shouldn't indiscriminately shove robots back every five seconds. This is one of the worst possible applications of airblasting and people will rightly get mad at you if you're constantly knocking around robots for no good reason. If people ask you to stop airblasting, please listen. This also applies to the Scorch Shot, which you shouldn't use anyway.

As explained earlier, Pyro is a very vulnearable class because it lacks a lot of options for circumventing damage that other classes have. Heavy can take resistances early or stick around a corner by the dispenser, Soldier and Demo can fire from cover or from far away, and Scout can dodge projectiles with double jumps. Doing damage with Pyro requires going almost totally out of cover and getting up close and personal with every robot you want dead, and that makes you an incredibly easy target-- meaning, you will swiftly get killed. There are many ways you can work around this: you can find routes or sources of cover that allow you to flame the robots before they notice you, you can use your Heavy as a tank and stick behind him when he's overwhelmed, or you can... use... a certain weapon other than your primary... that we'll get to later. On later waves, you might be able to afford full resistances in addition to full damage on your primary, in which case you can probably WM1 to your heart's content.

Afterburn is almost completely worthless and is not worth upgrading whatsoever.

The Do's and Don'ts of airblasting

Generally speaking, it is always faster to outright kill robots instead of delaying them or pushing them back. That said, airblast isn't completely worthless, but it suffers a lot from overuse from less experienced players. Ideally, you should never have to airblast, but it can come in handy in certain tough situations.

Examples of acceptable uses of airblast:

Examples of unacceptable uses of airblast:

Tips for using the Phlogistinator

The Phlog is generally considered to be the primary of choice for Pyro because its crits allow for easy melting of both robots and tanks. However, there are a couple of tricks to using it that might not be obvious at first.

The first trick is what's known as a "Phlog cancel", or a "Taunt cancel" or "Mmmph cancel". By activating your Phlog's Mmmph, you're normally forced to do a taunt lasting several seconds during which you are invulnerable and have crits, but you cannot use them as you are taunting. However, this taunt can be interrupted, and if it is then you will have an extra second or two of crits, as well as a second of invulnerability. The most consistent way to cancel the taunt is to land on top of a robot's head or on top of the tank, and taunt while standing on top of it. You should fall off in the middle of the taunt, interrupting it and giving you that extra second of crits. You can get on top of the tank or a robot by using the Detonator or the Thermal Thruster (I personally prefer the latter, but either will work fine).

The second trick technically applies to all normal flamethrowers, but is most useful with the Phlog. By crouching and pointing your flamethrower at an upward angle, your flames will do more damage. It's hard to explain why this happens, but it just does. If you correctly angle your flamethrower, your critical flames can potentially do up to 78 damage per tick against the tank, or 26 damage per tick without crits. This technique will make tankbusting much faster, but it can also be used against giant robots at point blank range, albeit less consistently.

Upgrade priority

You should try to max out your primary's damage as quickly as possible. The flamethrower, without damage upgrades, just doesn't do enough damage to be fully viable-- arguably not even on the first wave. Other than that, the Pyro's upgrades are pretty self-explanatory. Get relevant resistances, Health on Kill, ammo capacity and movement speed on later waves, and you should be good. Just remember that afterburn upgrades (burn time, burn damage) are useless. Airblast force should generally not be invested into.

Weapons

Primary

Secondary

Melee