MARIA: To get the Maria ending, stay close to Maria, don’t bump into her (much), and don’t examine the Mary-related items you get through the game (photo, letters) or the knife (from Angela). Try to revisit any room she’s in.
LEAVE: Keep your health level high, examine Mary’s letters and the letter to Laura. Don’t stay too close to Maria, don’t revisit rooms she’s in, don’t examine Angela’s knife. Listen to the hallway conversation.
WATER: Examine Angela’s knife, stay at low health. Read the diary on the hospital roof. Listen to the headphones in the hotel. Read the walls in Neely’s Bar.
You need to collect 4 items. The White chrism is on the kitchen counter in the Blue Creek apartment with the coin puzzle in it. Lost Memories book is in the newspaper rack in front of the Texxon station. Obsidian Goblet is in the Historical Society in a broken display case. Crimson tome is on the shelf behind the headphones in the hotel reading room after you watch the tape.
First you need to complete the other endings, then play through until you meet Maria in the park. Come directly out of the park, across the street toward the inn (but past the sign). You’ll see a small dog house. Check it for a bone-shaped key. Continue playing as usual until you watch the tape in the hotel. The neighboring room (check the map, the Observation room) can be unlocked with the dog key.
UFO: After beating the game a channeling stone will appear in the bathroom you start the game in (on the floor, opposite end as the door you leave from). Use the blue gem in the hospital garden after fighting the wall men, in front of the row boat on the dock, and in room 312 before watching the tape. NOTE: This is only on the Greatest hits and Xbox versions.