There is a workshop mod which gives you invincibility, you and your team will not die at all. So, you can start an Expert or Expert Realism campaign and can play as is and can get the achievements. This mod expects vanilla game to work properly.

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2367547552&searchtext=invincibility

But personally I think this is a total challenge killer (though will ensure the achievements 100%) and so also fun killer (no risk, no gain is failed here :D). But it is up to you to use this. I better now tell you about another method which will keep the challenge a bit alive...

Similarly, subscribe these 2 in your vanilla game...

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=236865433&searchtext=slow+zombies
And...

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2773596411&searchtext=double+damage+weapon+mod

Now you can kill everything faster and except tanks no special will spawn at all. Your team will not be surrounded by fast moving hordes. Yet, zombies will deal normal difficulty specific damages to your team which will keep some challenges alive in your entire game-play. However, during finale don't kick tanks (actually anytime 'kick Tank' is no longer necessary, I believe), because this may glitch your rescue.. Better kill tanks not kicking those and believe me, your team can kill expert mode tanks so fast that you can't imagine using rifles (even shotguns are not so important).

As 3rd way .. i am keeping my original old method as-is without any change.

I will describe you 2 methods for both of the achievements how to get with friends or solo with bots only.

So, first WITH FRIEND / FRIENDS…


By this method the achievement should unlock for the guest players other than the host.

I tested it with 1 player only but I believe this can be unlocked for maximum of 3 players at a time. This is for you people to test and report here.

Ok, now follow the steps below…

    
1. Start a “friends only” Easy Realism campaign with at least 1 friend who needs the achievement. However, you can start this with 2 / 3 friends also who need this achievement.
       
2. Play relaxed and together up to the last safe room before Finale. Never open the door of last safe room.
   
       
   • For DEAD CENTER the last safe room is before The Atrium starts.
         
   • For DARK CARNIVAL the last safe room is before The Concert starts.
         
   • For SWAMP FEVER the last safe room is before The Plantation starts.
         
   • For HARD RAIN the last safe room is before Town Escape starts.
         
   • For THE PARISH the last safe room is The Bridge starts.
       
3. Now the guest player(s) [those who need the achievement] should directly EXIT to main menu. Yes, main menu… no vote call or no return to lobby rather direct exit to main menu. After they exit to main menu the Host should send them invite to join the game again. But they will not join immediately rather will only wait at main menu keeping the invitation ready.
       
4. Now the Host player alone with bots will play the finale. I hope that the guest(s) will neither be much impatient nor will fell much boring to wait at the main menu because to complete the finale may take 10 to 12 minutes around for the host. For this achievement I will prefer DEAD CENTER campaign. There is a car and it needs 13 gas cans to be filled up. The host player should fill up 12 gas cans. The host should keep the remaining 1 gas can somewhere close to the car but should not fill it up. After the 2nd tank is dead and I hope you have already done fill up of 12 cans and you all [host and bots] are healthy enough [green health] should call the vote to change the difficulty in Expert. Stay in a little distance from the car as bots may shoot the gas can u kept near the car. Vote will be passed in no time as only host is present in game. This time host should be extremely careful to kill zombies as it is the EXPERT REALISM.
       
5. As soon as the vote is passed… host should call the guest players to join immediately. It may take 30 sec approximately (since the invitation was sent previously) for all the players to re-join. This is the most critical time for Host to defeat the zombies to stay alive.
       
6. After re-join (one of) the guest player(s) should take the last gas can and fill up the car. Now everyone try to escape. If all is done successfully the guest player(s) should get the achievement. Host will not get. If host needs this one then make other one as Host and you join him as a guest; that means need a new play through.

The guest player(s) who got this achievement… if yet not played the campaign for STILL SOMETHING TO PROVE achievement then this should increase their count by 1.

If you want to play any other campaign for this achievement then…

DARK CARNIVAL: The finale is The Concert. Follow all the steps like above. After the 2nd tank dies… change the difficulty into EXPERT and guests should re-join. By any means they should go to chopper [no incapacitated / death inside the rescue vehicle].

SWAMP FEVER: The finale is Plantation. After the wall is destroyed… call the vote. Rest all are similar.

HARD RAIN: The finale is Town Escape. Come out from the building and just towards the jetty, call the vote.

THE PARISH: The finale is The Bridge. After crossing the bridge take right turn and jump to the ground and call the vote.

Note: host must be careful that the bots should not ride the rescue vehicle before the guest(s). So, until the guest(s) are not re-joining do not be much close to the vehicle.


The method is almost similar like The Real Deal. But this time the host can start only EASY campaign. No Realism mode required. Then follow the steps same like above. After playing each campaign check your count.

Now, for the SOLO PLAYER…


Follow the steps below…

    
1. Start a “friends only” Easy Realism lobby campaign with the bots.
       
2. Play relaxed up to the last safe room before the Finale. Never open the door of last safe room.
       
3. Now directly EXIT to main menu. Yes, main menu… no vote call or no return to lobby rather direct exit to main menu.
       
4. Well, start a new Expert lobby now… a brand new lobby for EXPERT REALISM with the same campaign and the finale (last) chapter.
       
5. Now you need to survive this finale with the bots only. No other way is here. As a tip I will advise you to stay somewhere near the supplies. I played it solo and I practiced all the finales in expert realism and when could easily survived then got achievements by following this method. You can practice only one though.

I will prefer dark carnival and play from stage for several reasons. One reason is while the ordinary zombies will climb the stage your shots mostly hit their heads automatically from a distance if you are quick enough but be aware about spitter and smoker. Another reason is after the 2nd tank dies, you can see where the chopper is landing before rushing. I noticed in most cases at the right side of the stage it comes if you do not leave the stage until it arrives. That time take adrenaline and throw bile bomb and run, don’t care the bots. Some may find SWAMP FEVER finale is also easier for them... it's up to you.


Method is like same as above “The Real Deal”. But this time no realism is required. Rest all are same.

Players, who are using LOCAL SERVER, may use this command...

bind T "kick Tank; wait; kick Spitter; wait; kick Hunter; wait; kick Charger; wait; kick Jockey; wait; kick Boomer; wait; kick Smoker"

As a general reminder for all methods followers: If for some reason the finale fails, you all will be back to the last safe room for re-playing. Guests will exit to the main menu and host may change the difficulty to Easy. Rest steps are same. For solo players, no change of difficulty... retry again from there.

If you are someone who is getting problem solo or with the team to get the survival achievements, then you can try this method in your local server with friends or with bots and I hope success will be sure for you. Note that, at the time this guide is published, these are the rare to rarest achievements.



Anyway, for these, unsubscribe any other mods except the Double weapon's damages one I said above. With that subscribe this....

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=237538248&searchtext=Slow+Zombies

Using this mod all kind of enemies will spawn at normal rate but all will rush slow. So, naturally survival of 30 mints will be easy and no need to kick anything. Use rifles and pistols you will be able to survive in all maps 10+ mints with ease and your final status will be just normal as if you didn't use any mods. Test it. :)

Just as an example of a strange stats. see that some one clearly used "kick" or "tanks only" mod - whatever, and got such strange status (1 & 2). Using my technique no such "strange" thing will happen (3). :)
Just as an extra tips, for the 30 mints survival (SUPREME SURVIVALIST) I suggest HARD RAIN (Sugar Mill) map because it is my favourite but you can try at any other. For any survival stay near the supply if possible or if comfortable for you. If you are far from the supply then use pistol up to 5 mints to save rifle ammo. That's all and the most important part is if you don't die (death is not so easy anymore :D) just burn yourself to end the match - actually when you all human players will die the match will end and you will get your realistic stat. Good luck!

Even if this is not enough for you to survive long enough then there is one last way...
Subscribe this one with the 2 mods you have already. This will add 4 extra bots (not player slots) and very naturally everything will be the easiest..
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=121070254
Run your game and once it is properly installed you should see...
Next, click on CUS MUTATION and click on "Survival"...
After that, select "United We Stand"...
Finally, host the match...

Now, in the game you should see...


Oh! the last but not least, if your friends get problem to join you, bring up the console and issue this command: sv_consistency 0 before they join you. if you use this command, it is not necessary for your friends to install any of the other mods except Rayman1103's Mutation Mod described in this guide, only host needs these.

PS: If you have an older PC with low configuration and if you are experiencing lag, lower your graphics settings.

Achievement glitch: There is a known glitch for these achievements. Even after completing all the 43 maps if you see that the achievements are not unlocked yet, then load Death Toll -> Boathouse map. Once you are in, these achievements can unlock at a time. If any is not, then you need to load all the maps one by one and in one, the remaining achievement should unlock. In the details of the locked achievement in-game from the main menu, if you see a grayed-out chapter name - you can try to load it but it may or may not work though.

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=673457272

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2739114777

If you are a completionist, you may find it interesting...

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3445657955