Left 4 Dead

Easy way to do this one is to do a split screen campaign No Mercy Finale with two controllers.

Kill the two non human survivors in the safe room (switch to expert to do it quickly then switch back to easy). Then go out and up the steps with one of the human players. There is almost always a hunter somewhere at the top of the steps or in the hallway. Once you see him try your best to get back to the stairwell or as far towards safe room as possible.

Once you are close enough to the other survivor let the hunter pounce you. Pick up the other remote and get to the hunter who is pouncing. Make sure he incapacitates the person on the ground and then knock him off. Try to get in between the hunter and the downed character after you knock him off. The hunter should pounce the upright character next. Once he does pick up other remote and use downed character to kill the hunter who is pouncing, achievement unlocked.

Ironically I got this acheivement in No Mercy 5 in the Jesus Room by myself as the last survivor.
You can "save yourself" as part of this achievement. What I did was throw a molotov on the floor in front of me just as a hunter pounced me. As he started to hack away at my face the fire burnt him to death and the achievement popped.
Not sure if that helps anyone, but if you're ahead/behind the group, and you see a hunter about to pounce, molotov yourself =)

This is best done in Survival mode. Simply get overwhelmed, get incapped, and have your AI (has to be AI) team mates try to get you up. 80% of the time they get incapped or pounced. Tada, just shoot.

Ground Cover - 30G (Original Achievement)

Difficulty: 3/10

Your goal is to Kill a Special Infected that is attacking another Survivor while you are incapacitated on the ground.

You can do this with 2 People or two controllers.

You are Person A and your friend/other controller is Person B.

Start a level and change the difficulty to Expert, kill off the other two survivors, then change the difficulty back to Easy.

Person A open the Safe room door and stands in the entrance of it, killing any infected that come near, but when a Hunter appears back up into the safe room but stay in front of Person B. The Hunter will pounce on Person A.

Person B will wait until Person A is incapacitated and then Person B will melee the Hunter off of Person A. Person B should now get as close to the Hunter as possible to try and provoke it to pounce them. If it does Person A should now fire their Pistol/Pistols at the Hunter non stop to kill it.

I found this is the easiest way to do this solo.

Two controllers, No Mercy Finale on expert.

Shot the AI down and with your guest grab a pipe bomb and do the same steps described for the Zombie Genocidest boosting method:

(Run up the staircase; Drop pipebomb on corridor and run back to the safe room; Go back to the corridor after the bomb explodes. There should be a smoker a hunter and a boomer; Run to the safe room again.)

Now that you have your special infected waiting outside the safe room, use your guest to incap your main account then quickly call a vote for changing the difficulty to easy.

Open the safe room door with your guest and one of the specials should grab him. Shot it down and Bleep-Blop!

I got it first time when I came up with the idea.

Happy achievement hunting.

January 25th, 2021

MODE: Single Player
CAMPAIGN: No Mercy
CHAPTER: Rooftop Finale
DIFFICULTY: Expert

- First things first, KILL THEM BOTS... (The Shotgun works best)
- Then switch Difficulty to EASY
- Now grab a PIPE BOMB real quick and open the safe room door, shoot those zombies as ya head up the stairs toward the hallway and toss the PIPE BOMB to get rid of some of those zombies moping around.
- Once you hear/see that a special (or even a bunch of Zombies) is coming down the hallway, run back into the SAFE ROOM and close the door.
- Now grab a MOLOTOV and wait for a HUNTER. KILL everything else that may come knocking on the door.
- Once the HUNTER arrives (No zombies allowed), open the SAFE ROOM DOOR and and back up. As the HUNTER starts walking towards you, toss the MOLOTOV on the ground between you and HUNTER. (Just make sure you drop the MOLOTOV Before he pounces you, of course)

The HUNTER will pounce you and you’ll both burn and go to hell together. ACHIEVEMENT should pop when the gameplay starts to fade.

Make sure to have full health while attempting this method.