You mention not being too sure where the exit door is. I was under the assumption that the player would progress and eventually find the exit. Eventually that did happen of course. As for the confusion on what to do in the last chamber, I try to make sure I have all elements are neatly spaced out so that indicator lines don't get jumbled and criss-cross one another. I think the confusion just might happen to lay in the fact that it's unusual to implicate those 3 different elements to raise the platform. Which being
a cube on button (via tractor beam), a redirected laser, and a push button pedestal. It's not very often you see these 3 different elements combined to implicate the resulting action. Also, the fact that 2 elements are not timed, but the pedestal push button is. That too might make for some confusion. I will of course keep this knowledge in mind in the future because I like to make sure everything has intuitive flow to it. So yes, I'm glad you brought this up.
(F**king Windows right now is nagging me for a Java update as I'm trying to type this reply. I told it to knock it off and "no", don't update because you'll probably end up breaking something.) 
When you pushed the button to reverse polarity on the tractor beam and I saw that you reached over and grabbed the cube, I thought "oh damn, that's not suppose to happen."
The actual jist of that last part is to push the button to reverse polarity, wait till the cube gets pulled into the primary beam, pop a portal in that very last portalable panel above you (in the upper level), wait till the beam goes back to blue polarity and then that will deliver the cube to you. You will then have 2 cubes up there. I guess I should have put a glass panel beside the tractor emitter. Knowledge for the future I guess.
Thanks for complimenting the creativity on the second chamber. I was actually kind of reluctant to include that part. That's because sometimes, when you tractor beam the cube to a different place, the output can sometimes be cock-eyed and the beam will be pointed a little up or down and miss the collector. To fix that if it happens, the player just has to tractor it up and paste it against the ceiling to square it up and try again. It's just that some people might not know that.
Thanks for playing.