Sonic the Hedgehog Pocket Adventure
Chaotic Space Zone is an extra zone of Sonic the Hedgehog Pocket Adventure. The zone features last conformation with Dr. Robotnik in the game, as he escapes to a large, bulky robot, which has small resemblance to mech from The Doomsday Zone from Sonic & Knuckles. Sonic must have the seven Chaos Emeralds to access it.
This zone plays similarly to The Doomsday Zone from Sonic & Knuckles, even featuring a similar mech. It begins with the player having fifty rings. While normally playing as Super Sonic, the player has to collect rings from the extra zone while at the same time battling the mech. If the ring count goes to zero, Sonic turns back to normal and falls to the atmosphere losing a life. The boss moves up and down shooting missiles in different directions, which Sonic must dash into to reflect them onto the mech. The mech also shoots small sparkling projectiles all around the zone, which the player has to avoid. Otherwise projectiles will stun Super Sonic for while until the player got him again under the his/her control.
After destroying mech, Super Sonic gives final attack to Robotnik on his Egg Mobile, which falls down while exploding. Super Sonic then flies down to the Earth, lands to Tornado's wing and turns back to regular form. All seven Chaos Emeralds starting rotating around him and disappear on the screen with white flash. The music for this particular zone is an 8-bit version of Sky Sanctuary Zone. After clearing the zone and showing results, the game plays the fanfare music from Sonic the Hedgehog 3.