The handler for the A.C.G. door. It walks the three inventory slots four bytes at a time and wants $8C, $8D and $8E in them, in that order -- the three pieces of the A.C.G. key, ACG_KEY_PARTS -- and only then opens the door (OPEN_DOOR) and behaves as one, with a wider doorway than most. Anything less and it is drawn shut (SHUT_DOOR). Through it is room $8E, and reaching that ends the game.

New pickups go into the first slot, so this order means collecting $8E first and $8C last. Measured in the simulator: $8C, $8D, $8E opened it and walking in reached SHOW_END_SCREEN; the opposite order left it shut. The door is in room $00, the starting room, on its east wall.