Actually it's not, it's only nearly impossible - I just managed after a stupid amount of retrying and fiddling with mouse sensitivity - however even the devs seemed to think it was impossible because the journal indicates I intimidated him into not using 'roids - how annoying, my effort has absolutely nothing to show for it!!

I'm going to necro this thread, just because.

All you need to do is move the mouse left or right, trying to keep the icon on the yellow bar that shrinks as time passes.

The thing that makes the movement seem strange or sluggish is because the thing you're moving (the icon) isn't directly related to the mouse's movement, in the sense that moving the mouse right will increase the icon's speed to the right (or decrease it's speed if moving left) and thus moving the mouse left will increase the icon's speed to the left (or decrease it if moving right).

Instead of thinking of the mouse as a cursor or crosshair/reticle, think of it as a racing game where you accelerate or decelerate the car/icon based on moving the mouse left or right, and you want both cars to finish at the same time.

It's best to slowly/moderately accelerate at the start and make slight speed adjustments as you go along, you shouldn't have to move the mouse much during a match, just some smooth nudges. Though if you get the icon moving at the right speed near the start you can even let go of the mouse and watch it go all the way to a win. As long as you enjoy it who cares :)