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.
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.