Other mistake: In either scenario of Leon, when you enter the car park and meet Ada for the first time, she'll ask you to help her move the van blocking the way. On the side of the van, the word Emergency is spelt as 'Emergencey'.
Other mistake: In either scenario of Leon, when you enter the car park for the first time and meet Ada, she'll ask Leon to give her a hand moving the truck. On the truck, the word emergency is written as 'emergencey'. It might be a little hard to make out, but it's there.
Other mistake: In the Darkroom with the lights off (so that the flashlight is turned on), when the character stands in front of and faces the light switch on the wall, then turns the camera so it is in the doorway between the two rooms, you will notice that the flashlight beam passes through the wall, and doesn't go all the way to the back of the room. Not sure if this is the only wall that does that, or if all walls have that property, but I find it interesting.