This guide is a work-in-progress and may be iterated upon!

A "Demo" is a recording of your inputs used during gameplay which is recorded to a file that anybody else can then replay in their own running game as if they were playing it themselves, which makes it great for timing this category accurately! All it requires is usage of the developer's console and remembering to set a couple of key bindings. Examples of what you need to bind to reset each map successfully are at the bottom of this guide.

To enable the console, click Options > Keyboard/Mouse > toggle "allow developer console" to "Enabled". Now you can bring it up with the ~ key, to the left of 1.

The command to record a demo is "record" and anything after is what the filename will be. Entering "record YayFilename" would create a file called "YayFilename.dem" in your "Steam\SteamApps\common\left 4 dead\left4dead" folder. Once you are finished with a run, you can stop the demo recording manually by entering "stop" in the console.

For resetting the first level of any campaign, you can bind the "restartgame" vote to a key. To reset No Mercy 1, an example would be: bind v "callvote restartgame; stop; wait 1200; record ExampleBind"

For resetting any level besides the first one in the campaign, you can use the "changelevel" command. To reset No Mercy 2, an example would be: bind v "changelevel l4d_hospital02_subway; stop; record ExampleBind"

Change the key after "bind" to anything you are comfortable with using. A list of names for all special keys as well as more information on binding can be found here, https://developer.valvesoftware.com/wiki/Bind

Here are the commands you would want to bind for each level. Insert these after binding to your reset key of choice and modify the name after "record" to anything you'd like:

NO MERCY 1 - "callvote restartgame; stop; wait 1200; record NM1_Apartment" 2 - "changelevel l4d_hospital02_subway; stop; record NM2_Subway" 3 - "changelevel l4d_hospital03_sewers; stop; record NM3_Sewers" 4 - "changelevel l4d_hospital04_interior; stop; record NM4_Hospital" 5 - "changelevel l4d_hospital05_rooftop; stop; record NM5_Rooftop"

DEATH TOLL 1 - "callvote restartgame; stop; wait 1200; record DT1_Caves" 2 - "changelevel l4d_smalltown02_drainage; stop; record DT2_Drains" 3 - "changelevel l4d_smalltown03_ranchhouse; stop; record DT3_Church" 4 - "changelevel l4d_smalltown04_mainstreet; stop; record DT4_Town" 5 - "changelevel l4d_smalltown05_houseboat; stop; record DT4_Boathouse"

DEAD AIR 1 - "callvote restartgame; stop; wait 1200; record DA1_Greenhouse" 2 - "changelevel l4d_airport02_offices; stop; record DA2_Crane" 3 - "changelevel l4d_airport03_garage; stop; record DA3_ConstructionSite" 4 - "changelevel l4d_airport04_terminal; stop; record DA4_Terminal" 5 - "changelevel l4d_airport05_runway; stop; record DA5_Runway"

BLOOD HARVEST 1 - "callvote restartgame; stop; wait 1200; record BH1_Hilltop" 2 - "changelevel l4d_farm02_traintunnel; stop; record BH2_Tunnel" 3 - "changelevel l4d_farm03_bridge; stop; record BH3_Bridge" 4 - "changelevel l4d_farm04_barn; stop; record BH4_TrainStation" 5 - "changelevel l4d_farm05_cornfield; stop; record BH5_Farmhouse"

CRASH COURSE 1 - "callvote restartgame; stop; wait 1200; record CC1_Alleys" 2 - "changelevel l4d_garage02_lots; stop; record CC2_TruckDepot"

THE SACRIFICE 1 - "callvote restartgame; stop; wait 1200; record TS1_Docks" 2 - "changelevel l4d_river02_barge; stop; record TS2_Barge" 3 - "changelevel l4d_river03_port; stop; record TS3_Port"