During the first phase of the battle, the Big Arms mostly attacks by aiming and launching its punch at the player. However, it is easy to avoid getting hit by it. By the time it is launching its fist, it will lower its cockpit, giving the player the opportunity to hit the downward part of its cockpit twice; one before it embarks its punch attack, and another after the punch is embarked. If the player fails to use these opportunities to deliver an attack on it, the Big Arm will land aground and use its rocket to dash and hurt the player from the left to right and vice versa. After that, the Big Arm will return immediately to smack the player with its fist.
After four percents of its Health Gauge are depleted, the Big Arm will change its pattern of attacks, initiating the second phase of the battle. Firstly, it protrudes spikes on its arms and will try to punch Sonic from the edges and center of the arena. After that, it will appear from one of the sides and attempt to catch and toss Sonic into the ground, causing the player to lose Rings. When this happens, the player has to jump to the other side behind the Big Arm and move quickly toward it to damage the lower part of the cockpit using the Spin Attack. Continue using this opportunity to attack the Big Arm will help the player finish the battle.
It takes eight hits to defeat the Big Arm.
- 1-Ring Boss: Defeat Big Arm in 3:00:00 with 1 ring!
|0:00.00 - 1:00.00|
|1:00.01 - 1:30.00|
|1:30.01 - 1:40.00|
|1:40.01 - 2:00.00|
|2:00.01 - 9:59.99|
- On the original E3 demo, Big Arm had a remix of The Doomsday Zone theme, but it was changed by Gamescom to the correct remix.
- The remix features guitar solos that are highly reminiscent of themes from Sonic Adventure and Sonic Adventure 2.
- This was the very first boss stage that Sega confirmed would appear in Sonic Generations.
- Big Arm takes twice the amount of hits the Death Egg Robot can.
- Big Arm is the only boss in the Nintendo 3DS version of Sonic Generations that, on its original version, Sonic truly fought on his own. Sonic faced the Biolizard along with Shadow when it was in its final form, and he faced the Egg Emperor with Tails and Knuckles.
- This is the only stage in Sonic Generations that directly references Sonic 3.
- Interestingly, in Sonic 3 & Knuckles, the player had to go through Launch Base Zone in order to access Mushroom Hill Zone, but in Sonic Generations, it's the other way around (though Big Arm is not present in S3&K while playing as Sonic).
- Oddly, Classic Eggman is blacked out in the level select screen and the cutscene, but he is visible in the boss fight if you increase the brightness to 5.