The Super Eggman Walker is the true final boss, accessible only after collecting all seven Chaos Emeralds. This is a multi-phase battle that will test all your skills.
Phase 1: Ground Pound & Laser Cannon
Eggman pilots a massive walker mech. It will perform ground pounds, creating shockwaves, and fire a large laser cannon. The weak point is the cockpit on its head. When it performs a ground pound, it briefly lowers its head. This is your chance to attack. Sonic's Homing Attack is effective. Tails can fly up to the head. Knuckles can glide and punch. Amy needs to time her Hammer Jump. After taking several hits, it will transition to the next phase.
Phase 2: Flying Form & Homing Missiles
The walker transforms into a more agile flying form. It will fly around the arena, firing homing missiles and occasionally swooping down. Springs will appear in the arena to help you reach it. You need to use these springs and your character's aerial abilities to hit the cockpit. Tails excels here due to his flight. Sonic's Homing Attack is also very useful. Keep dodging the missiles and striking when you have an opening.
Phase 3: Ultimate Form & Multi-Lasers
The final form is the most dangerous. The mech becomes heavily armored and fires multiple lasers, energy spheres, and performs powerful charges. The weak point is still the cockpit, but it's exposed for shorter periods. Focus on dodging its relentless attacks. There might be temporary platforms or springs that appear to help you reach it. This phase requires extreme patience, precise dodging, and well-timed attacks. Keep your rings high and be prepared for a long fight. Defeating this form leads to the good ending. It takes a significant number of hits across all phases, roughly 25-30 total.