These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crowning Music of Awesome - The comedic dance remix song that plays over the end credits (the credits for when you beat the game, not the credits that you can access from the main menu).
Fridge Logic - The glass eye puzzle in chapter 7. Glass eyes don't function as actual eyes, but this is conveniently explained away by the All Just a Dream twist at the end
Putting the artifact in the statue's pillar in the first level. The statue then comes to life and starts bleeding (from the EYES!) and transports you to another world...yeah, bet you weren't quite expecting that, now were you.
The reveal of Mother and what exactly is happening to the kids in Chapter 2
Max transforming into Sarah at the end of chapter 3.