DemonStrate - Portal 2 - Challenge - Propulsion Intro - 18.51
I believe sub 18 is possible. I try to get the orange portal shot off between when Cave says "through" and when he says "60 bucks". I've gotten it as early as the end of "through" before, so it is definitely possible to do faster. Also, the shot isn't pixel perfect, but it depends on what resolution you are playing at. I'm at 1920x1200 on a 27.5" monitor, and it wasn't too difficult with practice.
You could eliminate the wall strafe with bunny hopping directly into the floor portal, but I found it to be difficult to time it for many reasons. You need to reportal, using the far wall as you are falling through the floor portal. That timing can be difficult too.
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