-force_vendor_id 0x10DE -force_device_id 0x0191 в параметры запуска. Если будет вылетать, то ещё Объём видеопамяти в настройках на средний или низкий.

+exec autoexec.cfg

Smarter Bots! In Left 4 Dead 1!
Sick and tired of Bots leaving you in the dust whenever a Hunter or Smoker takes you? Want to conserve those precious Health Kits for absolute emergencies? Here's a way to help:

Right-click on Left 4 Dead on your library. Select "Properties" and then click the "Launch Options". Type the following in the text box:

+sb_friend_immobilized_reaction_time_normal 0.1
+sb_friend_immobilized_reaction_time_hard 0.1
+sb_friend_immobilized_reaction_time_expert 0.1
+sb_temp_health_consider_factor 1.0

This will enter the above cvars into the game, bypassing the need to activate cheats. This will work in Single Player games, or in local games you happen to host.

https://steamcommunity.com/groups/l4d1lives/discussions/0/626329820761879891/

[--]Killer Queen (STEAM_1:0:36244157) is suspected of using a no fall damage bug.

Hordesize: 100-120 Zombies
Base-Tank-HP: 13000 HP
Retries Map/Camp: 2/11 Retries

cheaters
https://steamcommunity.com/profiles/76561197970370450/
https://steamcommunity.com/id/Solyaro4kin/