Ah, the Stanley Parable. It's such a good game, and a perfect demonstration of how to deconstruct the linear tropes of storytelling through subversive and narratively clever insights. Simply put, there's a lot of endings. And many of these endings are devilishly hidden. I've found maybe twelve so far, and I'm sure I still haven't gotten them all. With that in mind, here's a list of the more secretly hidden endings I've found. If you have found any that I missed, feel free to say so below.
NOTE: There will be massive spoilers in this list, since I'm explaining what the endings are, how to get them, and what happens in them. If you merely wish to learn how to get the endings without them being spoiled for you, just read the HOW TO GET IT section. You have been duly warned.
NAME: Stay Put
HOW TO GET IT: In room 427, at the start of the game, close the door while you're still in the room.
WHAT HAPPENS: The narrator talks about how Stanley, too afraid of what lay ahead, simply refused to leave, staying an indeterminate amount of time until the game restarts.
NAME: Window ending (the one that Yahtzee mentioned in his column)
HOW TO GET IT: In the first room after 427, you can glitch yourself onto a desk by climbing over a chair. You can then walk across to a window and clamber out of it.
WHAT HAPPENS: The narrator chastises you for thinking yourself so clever for finding that bug, and then presents you with a choice. This is actually two endings, and the dialogue is just as good as it always is.
NAME: Heaven
HOW TO GET IT: After you do one restart, a monitor in the first area displays the message INPUT REQUIRED. Click on it, and a bar will fill up some. There are five monitors like this, one appearing every restart, with the third inside the boss' office - just to confuse you. The fifth one is in Stanley's room, and when you press it, you are sent to heaven.
WHAT HAPPENS: Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons.
NAME: True Escape
HOW TO GET IT: When you enter the double doors in the boss' office, the narrator will start talking, and the doors will close. If you move quickly, you can double back into the previous room before it closes.
WHAT HAPPENS: The narrator stops talking abruptly, and the doors behind you open, all at once. Walk back all the way to the beginning, and you'll find a new door open. Take it, and you'll head up a long staircase before reaching a glowing cylinder marked ESCAPE POD. For all of this, the narrator is absent, suggesting you locked him in the room, and the game restarts as you enter the pod, implying Stanley escaped.
NAME: Whiteboard Ending
HOW TO GET IT: To be honest, I'm not sure. It happened for me when I completed the True Escape ending above and restarted a couple of times. You'll know it when you see it.
WHAT HAPPENS: The starting area is changed completely. The walls are colored differently, the room is different, and there are a bunch of closed doors with numbers. One can be opened, and inside is a whiteboard that says 'This is the whiteboard ending!' Other than that, the game is pretty much the same, and you can do a lot of the other endings after you find it.
NAME: Victory
HOW TO GET IT:...Okay, I really don't want to spoil how you get this, since it kind of ruins the whole point of it. Let's leave it at this: In the phone room on the disobedience path, instead of answering, there's something you can do that demonstrates true agency and choice. If you don't want it spoiled - and trust me, you don't - just leave and try it out. If you're a big fat cheater, read on.
HOW TO GET IT (MASSIVE SPOILERS): Oh, fine. In the phone room, unplug the phone. The narrator expresses surprise, and the ending starts. If you want to know more, you'll just have to play the bloody game.
So, that's all I've found. As I said, if you found some other hard to get endings, feel free to post them. Try to keep the spoilers to a minimum, though.
Bonus: Discuss the similarities and differences between the Broom Closet ending, and the Red Door ending. What do they say about the relationship between Stanley and the narrator? Explain.
NOTE: There will be massive spoilers in this list, since I'm explaining what the endings are, how to get them, and what happens in them. If you merely wish to learn how to get the endings without them being spoiled for you, just read the HOW TO GET IT section. You have been duly warned.
NAME: Stay Put
HOW TO GET IT: In room 427, at the start of the game, close the door while you're still in the room.
WHAT HAPPENS: The narrator talks about how Stanley, too afraid of what lay ahead, simply refused to leave, staying an indeterminate amount of time until the game restarts.
NAME: Window ending (the one that Yahtzee mentioned in his column)
HOW TO GET IT: In the first room after 427, you can glitch yourself onto a desk by climbing over a chair. You can then walk across to a window and clamber out of it.
WHAT HAPPENS: The narrator chastises you for thinking yourself so clever for finding that bug, and then presents you with a choice. This is actually two endings, and the dialogue is just as good as it always is.
NAME: Heaven
HOW TO GET IT: After you do one restart, a monitor in the first area displays the message INPUT REQUIRED. Click on it, and a bar will fill up some. There are five monitors like this, one appearing every restart, with the third inside the boss' office - just to confuse you. The fifth one is in Stanley's room, and when you press it, you are sent to heaven.
WHAT HAPPENS: Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons. Buttons.
NAME: True Escape
HOW TO GET IT: When you enter the double doors in the boss' office, the narrator will start talking, and the doors will close. If you move quickly, you can double back into the previous room before it closes.
WHAT HAPPENS: The narrator stops talking abruptly, and the doors behind you open, all at once. Walk back all the way to the beginning, and you'll find a new door open. Take it, and you'll head up a long staircase before reaching a glowing cylinder marked ESCAPE POD. For all of this, the narrator is absent, suggesting you locked him in the room, and the game restarts as you enter the pod, implying Stanley escaped.
NAME: Whiteboard Ending
HOW TO GET IT: To be honest, I'm not sure. It happened for me when I completed the True Escape ending above and restarted a couple of times. You'll know it when you see it.
WHAT HAPPENS: The starting area is changed completely. The walls are colored differently, the room is different, and there are a bunch of closed doors with numbers. One can be opened, and inside is a whiteboard that says 'This is the whiteboard ending!' Other than that, the game is pretty much the same, and you can do a lot of the other endings after you find it.
NAME: Victory
HOW TO GET IT:...Okay, I really don't want to spoil how you get this, since it kind of ruins the whole point of it. Let's leave it at this: In the phone room on the disobedience path, instead of answering, there's something you can do that demonstrates true agency and choice. If you don't want it spoiled - and trust me, you don't - just leave and try it out. If you're a big fat cheater, read on.
HOW TO GET IT (MASSIVE SPOILERS): Oh, fine. In the phone room, unplug the phone. The narrator expresses surprise, and the ending starts. If you want to know more, you'll just have to play the bloody game.
So, that's all I've found. As I said, if you found some other hard to get endings, feel free to post them. Try to keep the spoilers to a minimum, though.
Bonus: Discuss the similarities and differences between the Broom Closet ending, and the Red Door ending. What do they say about the relationship between Stanley and the narrator? Explain.