Community Mann vs. Machine strategy

General Strategy

• Teamwork is more vital than ever. Make sure to communicate at all times.
• The robots don't drop ammo, so take note of ammo placements and consider getting Engineers to place Dispensers at choke points.
• Always remember to reload whenever you get a chance.

Scout

• Due to the defensive nature of this mode, the Scout is at a disadvantage, with low health and short-range weaponry. To counter this, he's given a wider money gathering radius, gets health from gathering money, and respawns much quicker than the other classes.
• The Scout's role is not restricted to money gathering; with piercing upgrades his primary weapons can take out whole crowds of enemies at close range. Each of the Scout's primary weapons has its uses: the Scattergun has the bigger clip, the Force-A-Nature has knockback, the Soda Popper can build up periods of mini-crits, and the Baby Face Blaster can allow you to do damage from a safer distance.
• A hit from the Sandman's ball marks a robot for death like the Fan of War, meaning the robot will take mini-crits from your friends' weapons. Both the Sandman and the Wrap Assassin can also be upgraded so that more balls can be hit, meaning more targets being affected.
• Mad Milk is a great assisting tool, as anyone who hits a doused robot gets a health boost, and upgraded Mad Milk slows down wet robots, making them easier to hit. It can also be used to help root out Spy bots.
• Using Bonk! can allow you to serve as a distraction for giant bots, as well as grab credits without fear of being blasted to oblivion.

Soldier

• Upgraded banners can affect all teammates, meaning more ground can be covered rather than clustering around the Soldier.
• Be aware that Giant Heavies can destroy your rockets, and worse, Giant Pyros can airblast them. Consider using a secondary weapon against them.

Pyro

• The Pyro's airblast is one of the few ways to deal with ÜberCharged giants and can be upgraded to make separating a Medic and patient quicker.
• The Pyro airblast can also push bomb carriers away from the bomb hole.
• Whether dressed in fine suits or plate metal, Spies are flammable all the same. If the Announcer alerts the team to the presence of Spies, start Spy checking.
• Upgrading the regular Flare Gun to give it an increased rate of fire allows you to stack up critical hits on burning targets from a safe distance. Consider using this against giants and situations where it can be risky to get in close. Upgrading the Scorch Shot in a similar manner can also allow you to knock back targets and keep them from retrieving the bomb. Keep in mind that tanks do not catch fire, however.
• Using an uber canteen and your Axtinguisher can allow you to stand up to giants and take them down in short order.

Demoman

• The robots follow preset paths, so Sticky Bomb carpets are more effective than in normal gameplay. Upgrade for maximum effectiveness.
• The Critical Hit Boost Canteen can be used to make fatal sticky traps for giants and chip a chunk of health off of tanks.
• Consider using a Demoknight loadout and teaming up with a Medic with a Medi Gun. The ÜberCharge ability will allow you to fight in close quarters without harm, while collecting money the robots drop.
• Tanks are easy targets for your Grenade Launcher because of how big they are, while you can lay large groups of stickies on their predictable path to take a huge chunk of their health off.

Heavy

• Unique to Heavy is the unlockable ability to shoot and destroy projectiles with his primary weapon. Use this to counter Giant Soldiers.
• Penetrating primary fire makes an excellent upgrade against swarms of robots as your bullets can hit more of them at once.
• The Rage upgrade builds when you damage robots. Save the Rage for tougher robots like Heavy specials or Giant Robots (especially Giant Scouts), where they're easier to hit and more valuable to knock back.

Engineer

• Sentry Guns are vital for controlling choke points and dealing big damage to giants and the tank, but they attract Sentry Busters. Keep an eye out at all times.
• Sentry Guns will rebuild at an instant when hauling it to another location. This is a good strategy when the bomb carrier has breached your team's defenses or when taking down a tank.
• Use a Teleporter to make travel between base and front lines more quickly. It may make the difference between safety and Payload delivery. And remember, you can upgrade Teleporters to work both ways.
• Use your Wrangler if you have one. When you have a 100% upgraded Sentry Gun, the giants will fall very quickly.
• If a Sentry Buster gets too close, grab your Sentry Gun before it explodes, but be careful as it can destroy other buildings near its blast radius and can kill you if you are near it when it explodes.
• Use your Frontier Justice to rack up revenge crits very quickly from your Sentry Gun.
• Buying an additional Sentry Gun will let you place a Disposable Mini Sentry Gun so you can spread more damage with both Sentry Guns.
• Use Building Upgrades canteens to rebuild quickly if your buildings have been destroyed during a wave.

Medic

• To make the most use out of your canteen-sharing upgrade, use the Medi Gun with the opposite power, i.e. Use the stock Medi Gun with the Kritz canteen, and use the Kritzkrieg with the Uber Canteen.

Sniper

• Giants move half the speed than regular Robots (expect for Giant Scouts), making their enormous heads inviting targets, but they won't be an instantly killed like regular ones. Consider Rate of Fire upgrades to get more hits on them more quickly.
• Use Jarate to help teammates take out large groups of Robots or Giants quickly. Upgraded Jarate slows them down, making them easier targets.
• Spy bots will often hunt you down first before going after other targets. If you're in a spot by yourself, keep an eye out for them when their presence is announced, and consider hanging around your teammates until the coast is clear.
• Investing in piercing shots or using the Machina can allow you to take out multiple targets. This can come in handy when confronted with a Giant Heavy surrounded by Medic bots.

Spy

• Unique to Mann vs. Machine, the Spy's Sapper can be placed to disable robots. Unlike conventional gameplay, there's a meter that must be left to fill before they can be used again.

* Upgraded Sappers can disable robots in a radius and slow down giant robots to make them easier to destroy.

• Use your disguise to pick up money that is too dangerous for your teammates to retrieve.
• Be careful around Pyro robots. You might be accidentally hit by their flames, and once alight, any robot can identify you.

Map Specific Strategy

• The enemy team will usually have a planned path to the bomb location. Try to find out the robot's route at the start of the wave. Once your team have figured it out, focus most of your firepower there and locate chokepoints that you can easily pin down enemies.

Coal Town

• There is a hazard area in this map where Pyros may find convenient to airblast enemies into.
• There are many rooftops that players can use to their advantage.

Decoy

• There are multiple levels which players can use to separate themselves from the robots. Just be warned that the robots might attack you up there as well.
• There is a ravine in front of your base. If you need time, knock the bomb carrier into this ravine to stall it.