Hello all,

Welcome here.
If you are reading this guide, this mean you have experienced the same issues I got with this game to get some of the last remaining achievements.

Basically, all achievements could be unlocked with this version of the game (2018), except the Party animal.
But several are tricky to unlock.

And party anlmal is not possible (this is a broken achiement since the last update).
Here some clues for finishing all achievements...

Lets begin with the broken one.

Since the last update, in april 2017, it is not possible anymore to unlock this achievement.
Or at least, no one manage to explain how doing it.

But one player, Mercury, pointed that it is possible to redownload an older version of the game.
I tried it, and surprisinly, it worked !

Here are the steps:

• NO MORE WORKING type this in you web navigator (this activate steam console):
  steam://nav/console
  
  Now, we need to use an external tool for the same purpose.
  More details here:
  https://steamoss.com/discussions/forum/1/2823131412466237075/
  
  
• Download January 2017 version of the game:
  download_depot 360170 360171 6980166005766427148
  
  Need to adapt the command using the external application for depot (have not tried)
  
  
• Wait. It takes time. Dont restart steam (and obviously dont restart the computer).
  It is a 5.16 Go download, so be patient !
  
  
• When the console say it is finished, note where the depot has been downloaded.
  Should be something like steaminstall\steamapps\content\app_360170\depot_360171
  
  
• overwrite you game installation.
  This shall kept your save in place.
  (if you prefer, make a complete copy of the game folder. For info, saves are located in steam_installdir\steamapps\common\How to Survive 2\Data\Save
  
  
• Launch the game, your save.
  
  
• Then do the last party mission (christmast one)
  
  
• Finish the mission, and enjoy this damned achievement

[This may possibly work with other party mission, I have tried the last one, but assuming the game just need to check you have done all missions, doing only one of party mission could be sufficient)
I have not tried it, as I can unlock the achievement only once.

Strangely, this achievement could not be unlocked following the description.

Instead of speaking to everyone, just finish the game (I guess you already did this several times).
and then to the Kovak First elite mission

(The mission where you need to escort a zombi).

Just do this missing, and the achievment will be poping.

Some told they did not manage to to this, so I cannot be sure that it is the only condition. I just give my state when unlocking this achievement.

Maybe try to speak one to all NPC before doing the Kovak mission.

For both achievments, the trick seems to do all weapong and recepied in the same game play.

Therefore, accumulate enought ressources to build at once all items.
Vodoo guitar is not necessary (I have not the DLC, but still have the weapon achievement).

A trick to accumulate enought ressources:

If you are ready to cheat a little, you could use the save file to double the amount of ressources!

• with a character, load in your inventory all ressources you want to duplicate (you could go up to 6000, you will just walk slowly, so do it by day time
  
  
• Save and quit
  
  
• on your computer, go to the game installation folder, then in Data/Save
  
• make a copy of the wanted save (the one corresponding to your current character;
  SaveCharF_Public_slot X .ynm where X is the slot ingame of the character
  Put the save copy in another folder
  
  
• Return ingame, load your character, and just empty your inventory inside your trunk
  
• Save and quit
  
  
• On computer, restore the copy of the save in the original folder
  
  
• In game, load again.
  Then you have again all your ressources in inventory. and your chest also have the ressources.
  
  
• You could repeat the process untill you have enough ressources for all weapons and recepies

No real trick here.

Just to say that this achievement is not working very well.

each level is not necessary validated when performed.

What I can say it to perform the full series of pylon mission.

I needed to do that 2 or 3 times, before unlocking the achivement
(and it was never on the last mission, this really mean that a performed mission is not necessary saved as successful).

Thanks for reading.

This game was not really bad, I take a real pleasure with it.
But the achievement part is a little painfull by not working well.

I just hope I have help you with all this tricks.