Gray Mann has built an unstoppable automaton army with a single purpose: to destroy all things Mann Co. Luckily for you, the majority of this robot legion is equipped with basic weaponry that could never level an entire building. Unluckily, they also have access to giant bombs, which they’d drag through hell if it meant dropping one in a Mann Co. bombhole. And it’s up to you to stop them.
— Mann vs. Machine publicity blurb
Mann vs. Machine is a co-op game mode released in the update of the same name. In Mann vs. Machine, a team up to six players attempts to prevent a horde of AI-controlled robots from carrying a bomb to their base. Players can purchase upgrades for their weapons using in-game currency, called credits. All purchased upgrades will last for the duration of the game. If a player leaves during the game for any reason, providing they reconnect, their upgrades will be retained.
The team is attacked by a horde of AI-controlled robots, and must try to prevent the robots from successfully delivering a bomb to the players' base (as in Payload). Each robot destroyed provides the players with credits (when one player collects a money pile, it is divided equally amongst the players). At any time during the match, the players have the chance to upgrade their weapons at an Upgrade Station inside the base using this money. They may also upgrade abilities for their current class. All upgrade abilities are kept, even while switching to a different class, but the purchased abilities are only available for the class that they were purchased for.
Most of the robot horde is made up of plain robotic versions of all nine classes, including basic or mediocre weaponry. However, there are also a number of special robots with unique abilities.
While a robot carries a bomb, it loses half of its speed. However, the bomb-carrying robot receives buffs, which increase over time. A HUD graphic displays the amount of time until the next buff. Buffs are activated by the bomb carrier via taunting, setting off an accompanying audio cue. These buffs are divided into three stages, which stack together:
Players may use their accumulated credits at an Upgrade Station to fill their Canteens with a buff—such as personal ÜberCharge, a five-second critical hit boost, or ammunition refill—or an ability such as rapid building upgrades for Engineers or the ability to teleport back to the spawn point. All of these Canteens each provide up to three uses and must be filled with the same buff.
Players may also purchase personal abilities for themselves or for upgraded weapons.
Upgraded Sapper can disable groups of regular robots and slow Giants.
Spies' disguises fool all robot enemies; robots may detect a nearby backstab, and will always detect a Spy who is on fire.
Upgraded Knife can penetrate armor, allowing increasing effectiveness against Giants.
For the sake of identification, all human players are dressed as RED and identified as team DEFENDERS while all robots use BLU colors in their visual effects and in the kill feed. Games are played in waves, each containing a pre-set number of enemies. Various support classes also spawn in periodically until the wave is over.
Before each wave begins, Defenders are shown relevant information in the top HUD, such as the enemies the next wave will contain, the current wave, and the number of waves for that mission. Pre-set enemies have a number under each icon to indicate how many will be present in the wave, while support classes are listed to the right-hand side. A flashing blue icon means that the enemy or enemies will always fire critical hits. During pre-wave intervals, Engineers are able to instantly place level 3 buildings and Medics have a notably faster ÜberCharge fill rate.
When at least three players enter a Mann vs. Machine server, the option to ready up is enabled. Once one player declares they are ready, a 150-second countdown clock begins. As more players ready up, the countdown clock reduces to a minimum of 30 seconds until all players are ready. When all players are ready, the countdown reduces to 10 seconds. When the countdown ends, the wave begins. Players joining the server during the countdown will not increase the time.
When the wave begins, the top HUD will change to show a strength gauge to depict the quantity of pre-set enemies left. Robots will begin spawning in the battlefield in groups. Until they are on platforms that are accessible by players, attacking a robot will do nothing but cause them to glow as if they were ÜberCharged. During the wave, information about certain enemies may appear in the top HUD and will be announced by the Administrator.
Sentry Buster - Sentry Busters are large, bipedal stickybombs that will run, stop, and self-destruct near Sentry Guns. If an Engineer is moving their Sentry Gun, the Sentry Buster will chase them until they stop. These enemies only appear in response to effective Sentry Guns built by an Engineer on the defending team and will spawn more often if there are multiple effective Sentry Guns. A common strategy is for the Engineer to pick up their Sentry and run away from other players on the map and touch the Sentry Buster. This will cause the Sentry Buster to stop and it will explode. Another common strategy is for the Engineer to sacrifice their Sentry Gun by allowing the Sentry Buster to destroy it in a safe location. This will stop the Sentry Busters from spawning for a period of time.
Tank - Heavily-armored tanks will enter the field from specific entry points. They won't attack but will move implacably towards the bomb hatch until they are destroyed or reach their destination. They may crush any unfortunate player or robot that gets stuck between them and a wall. Tanks do not need to carry or retrieve the main bomb, as each one contains its own.
Sniper - Sniper Robots spawn like regular robots, but will mostly try to snipe players from higher platforms instead of running with the horde. All Sniper Robots except those carrying the Huntsman are unable to headshot.
Spy - Unlike other robots, Spy Robots may spawn anywhere where players aren't looking in the field by use of their cloaking. They can disguise as friendly players, backstab players, and can sap Engineer buildings. The Announcer will call out the number of Spy Robots remaining after each successive one is killed.
Engineer - Engineer Robots can enter in two ways - one, more common variation of the robot will teleport into the map near the bomb, while two rarer versions with half of the health will enter normally. Upon reaching a predetermined nest area, the Robot Engineer commences building a Teleporter, which acts as a forward spawn point for the robots, and a Sentry Gun to defend it.
After each successful wave, the defenders will be evaluated based on how well money was collected (with a credit rating ranging from F to A+). If all the piles of money are collected (the A+ grade), the team will earn a $100 bonus. Once a mission is completed, the defenders will be given a final evaluation, and the server will load the next Mann vs. Machine map after an interval of 20 seconds.
An example of the matchmaking screen when the penalty is applied
Introduced in the October 17, 2012 Patch, rules regarding players "abandoning" games have been implied.
A player is considered to have "abandoned" a game if they meet all of the following criteria:
Leave a game while playing a Mann Up game on an official server; and
Have not played through a single wave to completion or failure; and
There are 5 or more players currently connected to the server (including the player).
If they meet all of the criteria repeatedly, the player will temporarily be placed in a low-priority queue, resulting in a significantly longer wait upon matchmaking.
Otherwise, it is safe to disconnect a game without being considered "abandoning" the game.
If a player presses the disconnect button, the player will receive a message telling them whether it is safe to leave. The player will either abandon the game with a penalty or without depending on the occasion. However, if the player leaves by other means (such as changing server via console or the in-game Steam HUD), they will not receive a message and may get a penalty without being notified.
If a player loses their connection while in-game, the spot will be reserved for the player and will have 3 minutes to rejoin. If the player does not rejoin after the time is up, the player will have been counted as leaving the server intentionally. If the game has crashed or the player loses their Internet connection, then the player can then restart Team Fortress 2 and the player will be given a prompt to reclaim their spot in the match. This prompt will inform the player of the penalties they will get if they decline the spot. If the player fails to rejoin within the three minutes and they fill out the criteria listed above, then it will count the player as having abandoned the match.
If a player is kicked for being idling whilst in a match, then it will be counted as quitting intentionally and therefore will incur a penalty.
If a player is votekicked from a server, they will not be considered as leaving intentionally and will not incur a penalty.
Fixed a server crash related to damaging the tank with the new Medic shield.
Fixed bots trying to attack an old sentry location after the gun has been picked up by the Engineer.
Fixed a bug that would cause robot "gate hat" items to be craftable. Gate hats that were crafted while the bug was active have self-destructed and become limited-quantity Glitched Circuit Boards as a commemorative token.
Fixed the Health Regen MvM upgrade string mistakenly displaying %.
Fixed an exploit in Mann vs. Machine mode related to purchasing upgrades for free.
RED versions of all of the robots (besides the Tank and Sentry Buster) can be found in the game files.
Originally, Valve had planned for players to play as both BLU and RED team, as seen in the Mann Vs. Machine trailer. It proved too confusing in play tests however, and was inevitably removed.
Sometimes a menu such as team, class, or upgrade choice will freeze on screen, forcing the player to refresh the HUD. (This can be accomplished by typing hud_reloadscheme in the console or pressing Tab ⇆.)
When killed by a dead bot, such as from afterburn, or when removing a destroyed Spy bot's Sapper, the kill feed may show that the bot has moved to spectator mode. This is due to the internal routine that reassigns bot players for the next attack.
Sometimes after the wave is complete, the Administrator will continue to issue warnings about the bomb's progress. This does not impede progress in any way.
Bots will occasionally become stuck when jumping down into the map from their spawn. On rarer occasions this will cause the bot to immediately die upon touching the ground.
Giant bots have been known to die upon falling from a decent height, regardless of health remaining.
Bots that are destroyed while speaking and players who are killed while using Mann vs. Machine-related responses will continue speaking after their destruction/death. Tank Robots that are destroyed as they stop to deploy the bomb will continue to play the buzz and ding sound sequence.
It is possible for the Administrator to announce the team has failed the mission when they haven't, by destroying the bomb carrier as it is about to disappear into the bomb hole. The bomb hatch will be destroyed, but the game considers the bomb undeployed. In this case, the real bomb will never make it to the hatch as it will continue to kill anything that steps in to it.
Sometimes, when the map is finished, the loot screen shows up empty. This situation becomes recurrent for the player affected.
There is a small number of Sentry Gun placements that are immune to Sentry Busters. If the target sentry is in one of these areas, the Sentry Buster will spawn, and without jumping down or exiting spawn, they will blow up. This does not show in the kill feed, and the Sentry Buster icon at the top of the screen will remain.
Certain sounds will become stuck in a loop if a wave is failed while they are playing. A notable example of this is the sentry buster sound. This can be easily fixed by typing snd_restart into the console.
Rarely, before the round, the bomb will appear in the spawn points for the bots for all maps with no bot carrying it. An extremely rare case of this is the bomb being teleported to the hatch at start of the round.
Rarely, most of the robots' voice lines may not be robotized at all.
Robot Spies' voices will not be robotized when heard from a distance (this excludes the laugh that is constantly heard when they are present on the map).
Rarely, near the last third of the sixth wave on Big Rock, if one or more players leaves and is matched back into the server, the spawn rate of robots will drastically decrease, and most classes will not spawn at all. If a special class (Spies, Snipers) is active when this occurs, they will spawn in groups of two at a speed of about once per thirty seconds. When this occurs, friendly Sentry Guns will attempt to target players, though they will not do any damage. The only known method of circumnavigating this bug when it occurs is to restart the game entirely.
Sometimes on Mann Up servers there is a glitch where players cannot join the server. The only way to fix it is for every player to leave the server.
Rarely a Demoman Bot will glitch, with only his sword viewable, this bot can not be killed by any means known. Only option is to let the bots plant the bomb to restart the round. If players choose to vote to restart the round (because there are no more bots to kill or deliver the bomb and players are now stuck on an unfinished round) there is a small chance that the resulting restart will cause all bots to spawn more slowly. Although this may make the round easier to win it will increase the amount of time to win the wave (all waves are affected) to over 10 minutes per wave.
Very rarely, a robot may appear as a giant when it shouldn't be, or vice versa. Sometimes, the giant may still have the health of the smaller counterpart, or it may have the health that the giant version has.
Rarely, if a Engineer Robot's Teleporter is not destroyed and the wave ends, the Teleporter will not self destruct and continue spawning robots when the next wave begins.
Occasionally, if a Giant Robot is destroyed with the Medic's Projectile Shield, it will create a normal sized robot ragdoll with a proportional head size to the giant.
If a player is inspected during setup or mid-game, upgrades may be lost. If occurring during setup, money spent on the lost upgrades will be refunded. If occurring mid-game, however, there will be no refund on lost upgrades.
This happens most often with building upgrade canteens.
Rarely, Bots may stop spawning and cause the wave to be unbeatable, this can only be fixed by restarting the map.
Sometimes, when playing two Mann Up missions in one play session, the second mission completion loot screen might show the loot screen from the previous mission, also the advice for "Found Items" won't show up, items will still be obtained after updating backpack.