No Mercy takes place on top of Mercy Hospital,a map from L4D. Players will spawn on top of a platform next to a helicopter pad, which will be the landing spot for a helicopter that will be saving the survivors after they fend off zombie attacks.
When the round starts, the survivors would have to go to the radio to call for help. Afterwards, the survivors would have to survive for  minutes before the helicopter arrives to rescue the survivors. When the helicopter arrives, there will be  minute before the helicopter leaves and the survivors escape the map and win.
This gamemode is simple, but daunting. In such a battle space with no absolute protection against bat strikes, survivors rely on awareness to eliminate 100 player-controlled zombies in order to win the round.
Free For All
Survivors duel until one remains, who becomes the winner. If there are two survivors or more at the end of the round, no one will be victorious.
Mixed Martial Arts
All survivors fight each other with only their hands and feet.Survivors must kill each other using only hand combat until one person remains.If there are two survivors or more at the end of the round, no one will win the round,just like in Free for all.MMA(Mixed Martial Arts) is a more balanced version of FFA(Free For All),because everyone has the same weapons.
- Tanks can be easily shot off the building using grenades, chinalakes and RPGs.
- Mercy Hospital is one of the maps that spawn the most items for survivors.
- Survivors are prone to bat attacks as users are out in the open. EMPs recommended.
- The radio can still be activated on ELI, however, no rescue will be sent.
- The heli is glitchy and can often be seen BEFORE you call for rescue
- In Left 4 Dead on No_Mercy, you do not start on the rooftop of the hospital.