Mystery Of Rivenhallows has no Steam achievement nor any in-game achievements. The game can be completed in full in approximately 15 to 20 minutes, due to poor design, however, it is entirely possible to complete the game in less than 60 Seconds.

This video is a full / complete walkthrough for Mystery Of Rivenhallows, from start to end. It took me about 20 mins to complete the game and this video has been edited to remove thinking time and any mistakes I made to keep it as concise as possible.

As noted earlier, due to poor design it is entirely possible to complete Mystery Of Rivenhallows in less than 60 seconds. Want to try it for yourself...

Grab the key from the mailbox outside the orphanage.
Use the key on the orphanage front door.
Enter the orphanage.
Go upstairs.
Enter the bedroom on the right.
Complete the three dial puzzle on the shelves to the left (middle, middle, left, middle, right, right, middle).
Grab the hammer.
Go back twice.
Enter bathroom.
Zoom in on damaged wall at the back.
Use the hammer on the wall.
Grab the piece of paper from behind the tiles.
Game over.

I hope you found this guide of help, all comments, suggestions and criticism (constructive) is gratefully received.

An A to Z list of my Steam achievement guides and walkthroughs can be found @ https://cs2bus.com/sharedfiles/filedetails/?id=1502405720
If you would like to get a notification in your activity feed when I post a new guide, just click the "follow anrkyuk" button on my profile guide list...
https://cs2bus.com/id/anrkyuk/myworkshopfiles/?section=guides