Wing Fortress Zone

Wing Fortress Zone (ウィングフォートレス U~ingufōtoresu?, lit. "Wing Fortress") is the tenth Zone in Sonic the Hedgehog 2. Unlike the earlier Zones, Wing Fortress only consists of one Act, with a boss fight at the end of the Act.

Description
After his defeat in Metropolis Zone, the evil Dr. Robotnik flees to the skies in his secret stronghold, which is a flying battleship. Sonic and Tails pursue in the Tornado, chasing the mad scientist through the skies and catching up with the Wing Fortress. However, just as our heroes are getting close, Robotnik opens fire with a laser barrage, blasting Sonic's biplane out of the air. Whoever the player is controlling (Sonic or Tails) will make a leap from the little plane's wings onto the rear gantries of Robotnik's aerial stronghold. The player will have to explore Wing Fortress alone, even if playing with Sonic and Tails.

The beige aircraft contains all too many opportunities for Sonic to fall to his death, be it swinging hand-over-hand on the bars right next to the flaming booster engines, or jumping along retractable platforms set in the side of the ship, or being thrown over wide, open spaces by the launcher chairs which lie amidst the steel rigging. Vertical propeller blades are also on hand to chop the player up into pieces when they run into them.

Trivia

 * One of the more difficult portions of this level, the handrail section close to the beginning, can in fact be bypassed entirely, which is a great help both to Sonic's life count and to the player's time if they're an aspiring speed-runner. After the player destroys the very first Clucker chicken Badnik, balance on the extreme right of its emplacement, the player can jump up to a platform containing a Shield TV. From here, jump straight up, and an overhead propeller sweeps the player further upwards to the higher level, thereby avoiding one of Wing Fortress Zone's more annoying segments. The area where this shortcut is found is actually seen in the Sky Chase Zone as the Wing Fortress comes into view.
 * Dr. Robotnik's Japanese name is written on the Zone, despite being called "Robotnik" elsewhere at the time.
 * Note also in the picture to the right the early symbol of the Eggman Empire. Instead of a cartoony depiction of his face, the mad scientist instead used a stylized "EG" on the bulkheads of Wing Fortress.
 * This zone is an inspiration to Sky Fortress Zone Act 2 and 3 from Sonic the Hedgehog 4: Episode II.
 * Interestingly, in Beta 4 of Sonic 2, Wing Fortress Zone was called "Sky Fortress Zone" on the stage select screen.
 * Strangely, the two parts of the Wing Fortress Zone are not properly connected, not even through frame.
 * In the 2013 re-release when playing this Zone in Time Attack, the section after defeating the boss does not trigger the cutscene transitioning from Sonic to the Death Egg. Instead, a Capsule appears which marks the end of the Zone.
 * During the cutscene transitioning the player to the Death Egg, if the game's timer exceeds 10 minutes (the timer will still count as normal during the cutscene), the player will still die because of this. In the 2013 re-release version though, the player will not die and the timer will remain at 9:59.
 * Despite not appearing in the Simon Wai Prototype of Sonic 2, the music for this zone did.