I think I’ve found a bug. I’ve been exploring the level, when I found this final corridor with the three doors, and they just opened when I bumped into them, though I didn’t put the other spheres in place. (Screenshot attached.)
You might’ve forgotten to set them to locked.
And I think the crusher puzzle could be improved upon. The player is probably looking at the crushers coming down, not watching the door. Imminent threats usually draw away the player’s attention.
And even if the player notices the door opening in the last second, it can’t be reached if the player is on the farther side of the last crusher plate. It’s very likely that the player dies at least once before he or she could find the solution. I think trial and error should be avoided when designing puzzles. Also, the player doesn’t have to use portals.
I suggest reworking that part in a way that requires the use of the portal gun.
Here’s an example: There are five crusher plates, numbered 1-5. First, 1 and 5 starts to descend, then 2 and 4. The player is stuck under the third one, and that starts to descend too. “Oh, shit, what do I do, what do I do?” Then crusher number one start to ascend, and the player has to quickly escape there using portals. And then repeat this a few times. It’s not that hard to figure out, but there’s a time limit and other pressing matters, that should leave the player with a deep impression. Har-har.
Just a suggestion.
It’s a nice level, though.