Spin the tunnel so the gap lines up with your ship, then fly through it.
◀▶ or AD to steer  ·  on touch, hold the left or right half of the screen.
On a phone, tilt to steer — it turns on when you tap PLAY and allow motion access; toggle it any time with the TILT button.
Grab the gold orbs dead-center in the gaps to build a combo. It gets faster and tighter the deeper you go — spiral and slalom runs will test your nerve. Don't hit the wall.