This is having Maria follow you through the game, instead of leaving her at the hospital, discovered by Kinjit, I think, or at least Kinjit made some cool videos of it. This causes all sorts of weirdness, like when you meet her in the cell, she’s in the cell and also with you, so you can end up with 2 Marias in one room. One the downside, as always, if Maria dies, you die. In some places and on hard mode, this is problematic, especially the 2 PH fight. You have to pay attention to where she is and try not to let her die, not to mention try not to accidentally shoot her while aiming for something else!

How does it work? You need the Historical Society key right after meeting Maria for the first time. This lets you skip the hospital and go right to the Historical society. This is done with a trainer, but I’ve heard that the trainer itself may have a virus so I deleted it. However, I have this save file I made so you don’t need the trainer. Just unzip the save files and you will have save games with both Maria and the key. Load the “Town West” save, which is right after meeting Maria in the park, and go right to the Historical Society. This will allow you to play through the whole game with her following you.

Here is the save file:
mariaweirdness.rar