Fridge Brilliance: You start wondering how it was possible that Robin survived all those years, locked in the basement, all alone for years in an abandoned mansion, however you remember that in the last part of the game Michael receives an eviction notice, meaning that the mansion was sold fraudulently to him, also earlier when he impersonates Christopher Milton while phoning to the bank he can learn that Blackwood's bank account is still active. All of this point that Christopher Milton might still be alive which is confirmed in Last Visit.
It's hinted in the main game that somebody has been feeding him all these years, judging by all the blood stains beneath the window and the meat in the room.
There's a receipt from a butcher shop in one of the places Michael searches, also. For a large order.
Fridge Horror: If the curse was real the evil god sealed in the cursed mask will one day gain strength and break free, since the mask becomes unaccounted for at the end of Last Visit, and there are no more natives to keep it in check.
Fridge Logic: We never see Michael eating anything for THREE days, he even mentions on the first day that he needs to buy some food, except that the events ground him at the manor. Also, at the end of the game, there doesn't seem to be any lavatory in the locked part of the basement.
In Last Visit, the character comments on how the basement smells like a cat's been urinating everywhere.