Like the boss preceding it, the player has no available Rings in the Death Egg Zone to battle the Death Egg Robot with. This means that the player will lose a life and will have to start the battle over if they take damage just once.
After boarding the eponymous space station and beating Mecha Sonic, Sonic, Tails or Knuckles (depending on who the player chooses) chases after Dr. Robotnik, who escapes into his Death Egg Robot on the large hall. When Dr. Robotnik reaches and jumps inside of this battle armor, he proceeds to attacking the meddling hero.
If the player gets all the Chaos Emeralds and finishes as Sonic, a storybook-like ending will play with Tails and the small animals watching the Death Egg explode. Tails then gets into the Tornado so he can find Sonic in free fall. While flying, he spots Sonic, who activated his Super State sometime after escaping the Death Egg. The two then fly away and fly toward the screen. If the player fails to get the Emeralds, the ending is the same, but Sonic will land on the wings of the Tornado and will jump towards the screen.
In the iOS version of the complete ending, the Death Egg Robot is briefly seen in the end screen, completely ruined, while Dr. Eggman is throwing a fit, as Knuckles watches in the bushes.
When the battle begins, the Death Egg Robot starts out by moving very slowly towards the player. The player must jump and hit the body to damage the Death Egg Robot. This is a difficult task, because if the attack is timed wrong, the player might touch one of the hands and lose a life.
After a while, the Death Egg Robot will fly off screen and a lock-on target will appear and follow the player. Soon, the lock-on will start flashing and the Death Egg Robot will slam down, trying to squash the player. If the player manages to get behind it, the Death Egg Robot will launch a pair of spherical mines from the top of the mech's jetpack, almost certainly killing them. When it comes down, its hands will fire, attempting to hit the player. This Death Egg Robot is tough, as it takes twelve hits to destroy it completely. Repeating the process, the Death Egg Robot will break down and explosions will follow the player as Sonic (or Tails) will throw himself out of the Death Egg into space.
In Knuckles the Echidna in Sonic the Hedgehog 2, the Death Egg Robot is the hardest boss in the game with Knuckles. This is due to Knuckles' jump height being too low to hit it normally, so the player must do it as he lands, because as it crouches, it is low enough for Knuckles to jump and hit him.
- In the 2013 re-release of Sonic the Hedgehog 2, in addition to regular gameplay, this boss is also featured as the last boss fought in Boss Attack Zone. In this Zone, it is possible to fight the Death Egg Robot with Rings.
|"STH2 Death Egg Zone (Part 2) 〜Mega Drive version〜"||Masato Nakamura||2:18|