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, and the Soda Popper can build up periods of mini-crits).
• A hit from the Sandman's ball marks a robot for death like the Fan of War, meaning they will take mini-crits from your friends' weapons.
• Mad Milk is a great assisting tool, as anyone who hits a milked robots gets a health boost, and upgraded Mad Milk slows down wet robots, making them easier to hit.

Soldier

• Upgraded banners can affect all team-mates meaning more ground can be covered rather than clustering around the Soldier.
• Be aware that Giant Heavys 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 ubered giants and can be upgraded to make seperating Medic and patient quicker.
• The Pyro Airblast can also push bomb-carrier away from the bomb-hole.
• Whether dressed in fine suits or plate metal Spies are flammable all the same. If the Announcer alerts you to the presence of Spies start Spy checking.

Demoman

• The robots follow pre-set 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.

Heavy

• Unique to Heavy is the unlockable ability to shoot and destroy projectiles with his Primary. 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 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 denfenses or when taking down a tank.
• Use a Teleporter to make travel between the front lines and base quicker. 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 get too close, grab your Sentry Gun before it explodes but be careful as it can destory 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 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 destory 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 quicker. Upgraded Jarate slows them down, making them easier targets.

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.
• Use your disguise to pick up money that is too dangerous for your teammates to retrieve.

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 where players can use to their advantage.