I see a lot of confusion and misinformation about how the "Explosion on ignite" upgrade works in MvM. What this upgrade does is, when a robot covered in gas and takes non-afterburn and non-fatal damage, he will trigger an "explosion". This explosion will deal 250 damage to robots around the damaged one. The damaged bot will NOT take damage from that explosion. The radius of the explosion is similar to the Explosive Headshot one.

The Gas Passer works similarly to the Mad Milk and Jarate, which means more than one robot can be covered in gas. When a robot covered in gas get hit by a Gas Passer's explosion, he will only trigger an explosion himself if he survives it. This includes Heavybots and Giants. This can cause an explosion-spree on these robots, meaning the maximum damage possible with a single gas can on a single robot is (250 * (n-1)) with n being the number of robots covered in gas.

Additionally, the Gas Passer requires around 700 damage to recharge. This is rather big in normal TF2, but it's ridiculously low in MvM. The damage done by the explosion is credited to the Pyro, no matter who triggered the explosion. This damage done will recharge the Gas Passer. In short : if you have 3 robots affected by an explosion, the Gas Passer will be recharged.

TL;DR :

• Deal 250 damage to close robots if taking non-lethal damage
  
• Needs 700 damage done with any weapon to recharge, including itself
  
• Damage dealt to each robots assuming they have above 250hp : 250 * (n-1)

To understand how the Gas Passer's explosion on ignite upgrade made the Pyro absolutely too powerful, we need to understand how it worked before the Jungle Inferno update.

Pyro was mostly about dealing with Tanks. The Phlogistinator is still the best weapon to deal with Tanks, with only the Beggar's Bazooka and the Soda Popper able to somewhat compete with it. Even without the Phlog, the Pyro can deal a lot of damage with his other primaries, even including the Degreaser (as it doesn't have any direct-damage penalty).
The Pyro is also devastating against normal robots and Giants. However, due to his close range nature, he either needs to wait for the robots at a chokepoint or a corner, or to have his teammates distract the robots. Flanking a robot is actually much easier than players make it looks like : simply wait for the robot to shoot at a teammate and you're good to go.
At close range, a Pyro won't have trouble dealing with anything he can kill in a couple of seconds.
Additionally, due again to his close range nature, the Pyro can help with money collection. In theory, two Pyros can collect all the money a team will need.

So back then, the Pyro couldn't do three things efficiently : dealing long range damage, dealing damage to non-distracted targets and dealing with Uber Medics. He was, similarly to the Heavy, really ammo-dependant. He had to either look for ammo packs or go back toward the Engineer's dispenser on a regular basis.

The Gas Passer's explosion on ignite upgrade removes all of these weaknesses. There's nothing a Pyro can't do now. It can deal crowd damage to robots at a safe distance without having the robots distracted or needing to flank them, it can deal with Uber Medics and does not even need ammo.

On top of that, Pyro being able to kill Uber Medics efficiently makes Demoman and Sniper useless : why have a Medic killer when you can have this AND more ? The majority of classes that can fulfil the same role generally have major differences. Take Scout and Spy. A Scout can get the more more efficiently but, even if strong in these domains, can't deal as much damage as a Spy on Giants.

And even if it can't kill Uber Medics, the explosion on ignite upgrade is still the strongest AoE in MvM, far above the Explosive Headshot upgrade. You only 400$ compared to the Sniper's 1100$ to get a point in Explosive Headshot and max reload speed.

In short : the Gas Passer's explosion on ignite upgrade is an over powered upgrade on an already strong class.

Gas Passer played at full potential :
https://www.youtube.com/watch?v=0eugXSfFAuM

There are common arguments that keeps on coming back whenever people try to defend the Gas Passer's explosion on ignite upgrade. However, the majority of them tends to be flawed.


Pyro was always viable. Reasons as to why he's not in the Two Cities meta are not due to the class being "underpowered".

A bit of MvM history :

When the Expert tour Gear Grinder came out, one of the first meta team composition was born : Scout, Pyro, Demoman, Engineer and two Heavies. The Scout, Demoman and Heavies were noob-proof picks with a straightforward way to play them. Soldier was (and tend to still is) avoided due to the big amount of Pyrobots in the tour, able to reflect rockets right back into his team if he was not careful. Medic wasn't as popular either because players considered a player needed to be really strong at the class to compensate an other DPS class. Pyro was here for one thing : dealing with Tanks for cheap. Pyro was and still is the cheapest class in MvM and the strongest Tank killer. He could even deal with two Tanks at once, on maps like Mannworks.

When Mecha Engine came out, it was not an Expert tour with more breathing space for mistakes. Because it was advanced, it was also more accessible. Due to various reasons that may or may not include bias from lower level players (you don't need duplicates classes, so no double heavy), the missions being easier, with more money than any other tour before and players preferring gameplay variety, Soldier got his place back in the meta. Other classes kept their roles and, because Tanks are a major threat, Pyro was still here.

Now Two Cities. It gave a big buff and upgrades rework to the Medic. Everyone wanted to play him but the "no duplicate" logic was here too, so no more than one. Players realising they win with a Medic badly thought he was the reason the tour is possible, so he HAD to be part of the meta. But to replace who ? Well, since only two missions include Tanks and they aren't as strong as on the Gear Grinder and Mecha Engine tour, Pyro was the one to go. If Tanks were much of a problem, maybe he would still be part of the Two Cities meta.

You will notice I speak about tour-specific meta. Because Pyro is considered "not viable" by Two Cities players only. I am not saying you can't play the TC meta on Mecha, but not exactly the same way players are using it on TC.

Some screenshots of how viable Pyro can be without the Gas Passer (feel free to add some) :
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=584784849
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1259296351
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=796898409


And the Medic and Spy have no impactful primaries in MvM and I see no one complain about it.

And Pyro have other decent secondaries. The Flare guns allow for nice long range damage (to charge the Mmph bar of the Phlogistinator for example) and the Detonator, Scorch Shot and the newly added Thermal Thruster allows for more mobility to flank the robots.

Even if the Pyro had no good secondaries, he still have a strong primary which is the best Tank killer. It's like complaining about a puppy in a luxurious estate not having a golden plate to poop into.


Demoman and Sniper tends to be aimed by these. They can deal a lot of area damage. I already explained that not only they need ammo, but Demoman needs preparation, Sniper needs to do headshots and that they can't do this with only 400$.

Additionally, the Demoman can't properly deal with Tanks and Sniper is a really squishy class that can't fight at close range. Things Pyro can do. Demoman, Sniper, and any other class have weaknesses to compensate for their strengths. Pyro, with the Gas Passer's explosion on ignite, don't.


It technically made the Pyro CLASS easier to play, but the skill floor for a flamethrower-based Pyro did not change. It's simply a crutch : something that gives more power for less skills. The way to play Pyro simply switched from "flank robots and don't go on them while they are aggroed on you" to "throw the gas can".

And even there, rare are the players that can play Gas Passer Pyro properly : people throwing the Gas Can on single bots, going flamethrower after a throw despite the Gas Passer being fully charged again and facing groups, or even missing groups of robots with it. Something made idiot-proof, but all we only got better idiots.


I actually made a guide for that, so I don't have to hear it again :
http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1274215055
That way, you can get your loot.


I know people that likes to carry new players. But they do this more for the challenge rather than to "get that mission done". Additionally, who do you think deserve to win in the most difficult missions, the guy that knows a lot about MvM and uses all his skills and experience or the low level players getting carried ?

Additionally, if the higher difficulty tours are accessible to everyone, then what's the point of this difficulty system ? Why have Normal/Intermediate/Advanced/Expert when everything can be Normal and be done with it ?

People playing PvE games might understand. How fun can it be without challenge ? Why defeat something if it is incredibly easy to do ? You do it once or twice, but since it's so easy, what's the point ?

There's actually a community of MvM players that likes its challenges, which I am part of. Beating the mission with lower-level players, finding how much you can change your playstyle, or give yourself incredible challenges. And sharing this ! Sharing all you have learned, to help others improve and love this as much as you do, by marking down what works and what don't.

And then, you have the Gas Passer throwing everything away. Destroying what was left of what looked like a challenge. Putting what is left of a "Meta of roles" under 6 feets. And learning ? The Gas Passer is the fastest way to reach full potential in MvM. If everyone is a pro MvM player, no one is.

Now that would actually be selfish to complain about something without even trying to look for possible solutions.

The problems with the Gas Passer's explosion on ignite upgrades are the following :
- Allows for easy AoE with explosion cascades
- Can deal with Uber Medics with the 250 damage output
- Only 700 damage to recharge

The easy solution would be to delete the upgrade overall (and replace it by a standard "slowdown upgrade"), but if we were to keep it, how to not make it too powerful ?

• Prevent robots taking damage from an explosion from triggering other explosions
  This should prevent the weapon from dealing incredible damage to everything. Only one explosion and no exponential damage output. It can be done by giving the robots a TF_COND_EXPLODED for example.
  
  
• Set the explosion's damage below 150
  Not only it will furthermore reduce the damage output, but also prevent the weapon from being able to kill Uber Medics. I also heard a suggestion where the damage done could be increased with a multiple-level upgrade. Could be good, but maybe it should not go above 150 damage.
  
  
• Triple the damage needed to charge the Gas Passer
  700 isn't a lot in MvM, but 2100 is actually a reasonable number. It would also give a reason to buy the recharge rate upgrades. There's already weapons that needs to charge more in MvM, like the Phlogistinator.
  
  Well, I'm sure we can theorise about how to make the Gas Passer not overpowered in MvM, but if Valve or the TFTeam is unwilling to listen, then what's the point ?
  
  You can actually make that change : simply send an email to the TFTeam ( http://www.valvesoftware.com/email.php and select "TF Team"), send them a short and polite email about the Gas Passer's explosion on ignite, and link this guide if you want. You can also link them the Big community MvM changelog : https://docs.google.com/document/d/1kbXNmDzrO9Mq2Zv-VgtrkkxrVn3rhi-Jo2Rnjn9_ERA/edit?usp=sharing
  This changelog was passed around MvM communities and suggest simple and explained changes that would be appreciated for MvM. These are bug fixes and balance changes, including the Gas Passer change above. You are yourself able to comment on it if you want, no matter you level in MvM, in the Google Doc itself. You can also share the link to anyone you want.
  
  I want to finish this by saying : Thank you. This big guide is just a rant by itself, but you took the time to read it. And even if you did not send any email to Valve, I want to say Thank you for the time you took to read this guide, and I hope you have a nice day.