The story-based achievements are impossible to miss. You get them by playing through the story of the game. This means that as long as you finish the game, you should have all of these achievements.

Summer '06
• Finish Chapter 1

Autumn '06
• Finish Chapter 2

Winter '07
• Finish Chapter 3

Spring '07
• Finish Chapter 4

Summer '07
• Finish Chapter 5

These achievements are found by entering codes in the gallery where you can see your profile pictures.



All of the secret profile pictures are references and they are unlocked by typing in what the reference is. If you want to find out the references for yourself, I advise you to click off this guide.

• grimecraft

• rickandmorty

• idubbz

• hypnospace

• minecraft

• kindafunny

• makesail

• nightinthewoods

• fivenightsatfreddys

• kreygasm

• kappa

• va11halla

• newgrounds

• overwatch

• tacoma

Merely unlocking the profile pictures will not unlock the achievements. To unlock the achievements, you have to start any chapter, and you should see another friend in your friend list. Click on the friend and interact with them until you get the achievement.

The page looks like this:
This one is for the "Is Herobrine Real?" achievement.

http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=949930351
This guide shows you how to get the hidden achievemenet.

I hope this guide helped you.

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