[PTI] Singularity
One single laser is used throughout the puzzle. There are reflector cubes used along the way to redirect the laser as you progess. There's a bit of back and forth, but really there's no excess walking. It's just a matter of jumping back down and returning through portals. It gets a bit tricky as you progress, so I would rate this between medium and hard.
Pretty good map except the part where the cube must land perfectly on the button. That part was just pure evil. 
Here's my blindrun:
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Tell me if there are any unintended solutions! 
4/5. Great.
Thanks for mapping! 
Cheers! 
That last part was unintended. I wasn't expecting that.
. The solution is to put that cube from the adjoining dropper on the button. It then lowers the fizzler field. You then pop a portal in the other room above the grated barrier. Push the button again and drop another cube. It then lands in that area above the grated barrier. This means fizzle the previous one. Once that cube is up there, you then portal your way up there. You then sit it on the glass flip panel. Go back down to the first cube and momentarily lift it off the button. This will cause the flip panel to open and the cube will drop down below the grated barrier.Thanks for sharing your video. I'm going to upload a walk-thru video soon.
Fairly difficult for me, but managed to get through with a bit of muddling around with the laser redirection.
I will look at Rectors video shortly, but I didn't have to throw any cubes (good thing, I'm terrible at cube tossing). Will be interested in your intended video...Thanks for creating yet again....
Video walk through