MISSABLE ACHIEVEMENT/TROPHY ALERT!
Chapter 8 sees a return to the more familiar style of test chambers, with your former 'friend' at the helm. None of these puzzles are amazingly taxing, but of note is the Achievement/Trophy awarded for breaking every one of the TV's in each of the chambers. Luckily we've got a video of that in our Achievement/Trophy section...
Also, the intro part is extremely linear, so you should breeze through it without any issues at all.
When you enter the 'first' chamber (where you have to hit the button), simply stand still for around 30 seconds or so and you'll get the 'You Made Your Point' Achievement/Trophy for your 'efforts'.