Now seeing the solution I realized that this is a map that requires ninja skills to solve. It would be convenient if you had warned course description. I was also disappointed to see that modifying the tractor beam does not make any difference in solving the puzzle.

video

I would be very happy, if a Walktrough (with intended way) was published...

No thumbs up for being a confusing map and get stuck in the cube button that activates the gel. But also without thumbs down by introducing a new element to game.

I recorded my gameplay (valve DEM file format): Download [dl.dropbox.com]

Turrets highly explosive. Handle with care

completed with repultion gel.
did not see what triggered panels opening.
when I got cube on button, that activates repultion gel,
the panels revealing the funel were closed.
so thought it was a red herring.
I even removed the cube & destroyed it, to see if the panels would open.
but they did not.
even though after exiting, I went back with noclip & saw a button to activate the funel.
so tricky getting the cube & getting to exit with repultion gel,
that I did not enjoy it.
in fact this was not my 1st attempt.
so sorry, no thumbs up.
but no thumbs down either, as it was solvable.

Honestly, if you're going to introduce a non-standard element like a super repulsion beam, at least put some hints on how to use it. Every time I did, I got thrown in a random and super-unhelpful direction. Not fun.

I probably did some things in an unintended way. Getting the cube: I put a portal on the wall, went through a floor potal, and used two portals on the floor to go through the fizzler, grab the cube, and somewhat throw it over the fizzler. Can't believe I didn't see the 'normal' way, but that works. Like probably anyone else, I tried using the slanted ramp with blue gel to bounce sidewards, but didn't pull it off, so I used the beam. Oh, and I didn't use the ramp at all: I got to the beam button by jumping up on blue gel and into the pit with the cube and portals set up.

So I actually took the time to complete it. Pretty cool. I did use the beam at the end (no idea how else to do it).

I got stuck in the first room by putting the cube back in the dropper 8D

Superfowerfull tractorbeam...but I didnt need to get to the door...