Sky Chase Zone (Sonic the Hedgehog 2)

"Robotnik has escaped to the sky! Sonic's a wing walker (and "Tails" is his pilot!) in a perilous battle above the clouds!"

- Sonic the Hedgehog 2 manual description

Sky Chase Zone is the ninth Zone in Sonic the Hedgehog 2 and the first of three consecutive single-Act Zones that conclude the game. Located in the skies above West Side Island, it follows Sonic after he has managed to drive Dr. Robotnik off the island. Robotnik has now fled his massive Metropolis base and traveled to his airbase, while Sonic and Tails give chase in the Tornado.

Overview
In Sky Chase Zone, the Zone is constantly moving forward via auto scrolling. The player (Sonic or Tails) will be standing on top of the wings of the Tornado, giving the player very little space to stand on. The secondary character will be in the cockpit, flying the plane. The player will have to fight the airborne Badniks as they move towards the Wing Fortress. The player is able to move Tornado the same way as the playable character, while also being able to Spin Jump and Spin Dash. Pressing up or down on the D-pad also move the biplane for the respective directions. As for moving and jumping, the Tornado keeps following below the playable character, but does not respond as fast as the playable character during sudden movements.

This Zone does not have any items or obstacles except Rings and Badniks. This level scrolls to the right automatically, so it is possible for Sonic/Tails to get stuck between the left side of the screen and another Badnik if the player isn't fast enough. The player has to avoid getting hit by fast moving Balkirys, avoid both Nebulas and Turtloid's projectiles. After destroying smaller types, the player can also stand on larger Turtloid to get better place to move.

At the mid-point of the Sky Chase Zone, half of Wing Fortress Zone is seen flying right past the screen. Due the auto scrolling, it takes at least two minutes and six seconds to complete the Zone. Sonic and Tails move off the screen as progressing to the next Zone.

Trivia

 * Sky Fortress Zone Act 1: "The Tornado Takes Off!" from Sonic the Hedgehog 4: Episode II has similar structure compared to Sky Chase Zone with more obstacles and platforming sections.
 * This is one of the two Zones in Sonic the Hedgehog 2 not to be featured in Boss Attack Zone, the other being Hidden Palace Zone (three if counting Proto Palace Zone).