Hey!

There are 5 achievements.

Three of the achievements are missable (plus one of those is time sensitive), but all can be unlocked in a single playthrough.

Boundary Crosser - Discover the exit is sealed.
Interact with the big door.
(In the video it's at 1:32)

Unholy Relic - Find the severed arm.
You will unlock this when you pick up one specific 'ingredient' of the five that are necessary.
(In the video it's at 6:05)

Static Liberator - Break all the TVs.
After you pick up the hammer, you have to find and break 3 TVs.
(In the video the hammer is at 5:30
TV1 = 5:40
TV2 = 7:30
TV3 = 9:37)

Procession Begins - Complete the ritual successfully.
You will unlock this when you finish the game.

Swift Passage - Complete the game under 15 minutes.
Finishing the game in 15 minutes isn't too difficult. You don't have to rush like mad, but don't stand idle for minutes either.

If you have any questions, suggestions, criticisms, found any mistakes and so on, please let me know!

Thanks to the developers for making a good game and thank you for checking out my guide!