I am sure the companion cube was used in a test of yours before...
Anyway, I like the first phase of the test, although it features a way to make winning impossible, forcing you to kill yourself or restart the game, and simply being nothing totally new.

The second part was way more complex than it had to be.
By that I mean the room layout, the rooms just felt wierd and too big.
Also, connections are often unclear or look wierd, there is a door with an antline next to it.That antline is next to what looks like a second antline, but it's the same.

This might be my favorite test chamber because I managed to do an actually big brain test, but Part 9 will be awesome, I can guarantee it.

I got trapped because I took the cube with me when I should not have.

Good use of cube and bridges - nice looking map - thanks for creating

Cool! Thanks for sharing.

Thank you!
Be tuned for more because next time we're going to go to behind the tests!

Really well made!