In the next room interact with the veil, then go to the top left room where there is a memory puzzle. In this puzzle you are supposed to follow the path of the Celestial and select which number is the pattern the Celestial followed. You can press enter to make the Celestial to follow the path quicker. The answers are 3, 1, and 3.
After you leave that room proceed to the top right room. First interact with the light switch, then go to the room on the right. Search the top two bags inside the room to get the EULI and Matches. Interact with the halo and wear it, then proceed to the room on the left. Interact with Rem and select "set on fire". Switch the lamp off. Interact with the papers and select "listen in", then interact with them again and choose "tear apart".
After you are back in the main room buy the Indulgence: Square with your EULI. then interact with the veil and proceed.
After the intial dialogue interact with Rem go to the bottom left room. In this room you walk around and interact with shadowy figures representing Celestials.
Make sure to run along the wall on the left to get the EULI in that room. Once you have gotten all the Celestials dialogue will play and you will leave the room.
Then go to the bottom right room. This is a chess puzzle. Push the Conducter statue to square F7 and then stand Ori in square H6. It should end up looking like this:
Then press the T key.
Once back interact with the violet sparkle to get the Rosary. Use your EULI to buy Indulgence: Circular. Interact with the veil.
In the next room interact with the veil. After this, interact with the indulgence dispenser to get the free Indulgence: Cross. Note here that you need to have all your indulgences and have interacted with them all to get ending: noise. This is your last chance to do so.
Interact with the top right room, then enter the top left.
After this is another puzzle. You can find hints in the upper right corners of these next three rooms. Follow Ori through the doors of the first two rooms, which are triangle and circle. After that, if you follow him into the circle door, you will default to the silence end. If you choose to go through the triangle door instead, you will be met with a different sequence of doors. From here, go through cross, square, then square doors to proceed with the noise ending.
In the next rooms while you are in Ori's view interact with the statue and take the lantern and then ring the bell on the desk. Go to the left room and interact with the Puricas at the top of the room. Go back through the main room into the left room and then interact with the sign in front of the statue twice. Press O to switch to Rem's view and then pick up the violet objects off the ground. There should be three, one in each room.
Switch back to Ori's view and select all three objects. Then interact with the veil.
If you got the:
ending: silence
Interact with the Rosary with R and select "what should I do" then interact with Rem. This will trigger the ending scenes.
ending: noise
Run up the stairs and let the scenes play. Once back in the hotel enter the bottom left room then enter the room on the left and get inside the closet.
Near the end of this ending, you will be presented with a choice to either "close your ears" or "listen in to the noise". Choosing to close your ears will prompt an afterword from the creator Etherane while choosing to listen into the noise will show more story regarding Mari.