Not too sure about this one - in the room with the cube you don't need either the yellow portal or the panel which juts out from the wall, and I'm generally averse to unnecessary elements in chambers. Especially here, as it made the puzzle look like it was going to be a lot more complex than it actually was, leading to a feeling more of disappointment than satisfaction when I found my way to the exit....
Using only one portal was fun once again !
The only thing I did not like on this was the ratman soundscape playing on loop after you'd enter the secret room.
I think you should MAYBE remove the deathray, it had no real purpose. :S Or did it ?
I always like puzzles that show the exit right at the beginning and propose a way around it :>
Okay the new and updated version is online; this time with all the changes it should've had when I updated it earlier. So the easteregg is much better; and there are a lot of other, smaller fixes as well!