To unlock the Sega version of Sonic the Hedgehog, purchase the sega controller from the shop located to the left of Green Hill Zone. After that, take the controller to the Sega Console located in the top left area of Green Hill Zone.
In the Collection room, position Sonic to the right of the Movie Chair to the left of the Art painting. Now hold BACK to enter a trap hole that takes you to the Statue Room. Unlock the following statues by entering the corresponding passwords:
STATUE - PASSWORD Aero-Cannon - 329494 Amy Rose - 863358 Big the Cat - 353012 Blaze the Cat - 544873 Booster - 495497 Buzz Bomber - 852363 Capsule - 777921 Chao - 629893 Chaos Emerald - 008140 Charmy Bee - 226454 Chip - 309511 Chopper - 639402 Classic Eggman - 103729 Classic Sonic - 171045 Classic Tails - 359236 Cop Speeder - 640456 Crabmeat - 363911 Cream the Rabbit - 332955 Cucky/Picky/Flicky/Pecky - 249651 Dark Chao - 869292 Dr. Eggman - 613482 E-123 Omega - 601409 Egg Chaser - 200078 Egg Fighter - 851426 Egg Launcher - 973433 Egg Pawn - 125817 Eggrobo - 360031 Espio the Chameleon - 894526 Goal Plate - 933391 Goal Ring - 283015 Grabber - 275843 Gun Beetle - 975073 Gun Hunter - 668250 Hero Chao - 507376 Iblis Biter - 872910 Iblis Taker - 513929 Iblis Worm - 711268 Item Box - 209005 Jet the Hawk - 383870 Knuckles the Echidna - 679417 Metal Sonic - 277087 Miles "Tails" Prower - 632951 Moto Bug - 483990 Omochao - 870580 Ring - 390884 Rouge the Bat - 888200 Sandworm - 548986 Shadow the Hedgehog - 262416 Silver the Hedgehog - 688187 Sonic the Hedgehog - 204390 Spinner - 530741 Spiny - 466913 Spring (Red) - 537070 Spring (Yellow) - 070178 Vector the Crocodile - 868377
ACHIEVEMENT - HOW TO UNLOCK (Hedge)Hogging It All Up! - Got all collectibles. A 30-Second Test - Participated in a 30 Second Trial. A Quick Breather - Got the Red Star Ring atop the highest spot in ROOFTOP RUN. Action Hero - Performed all of Sonic's actions in Act 2. All Stages Clear! - Cleared sonic generations. Big Bang - Got Rank S in all acts. Blazing Meteor - Got Rank S in acts seven times. Blue Comet - Got Rank S in acts 12 times. Bonds of Friendship - Completed all of Sonic's friends' Challenges. Boom Boom Dragoon - Defeated egg dragoon. Bright Star - Got Rank S in an act. Can't Touch This - Took no damage while defeating the final boss. CHEMICAL PLANT Restored! - Restored the CHEMICAL PLANT Stage Gate. CITY ESCAPE Restored! - Restored the CITY ESCAPE Stage Gate. Color Power! - Got the Red Star Ring by using an Orange Wisp in PLANET WISP. CRISIS CITY Restored! - Restored the CRISIS CITY Stage Gate. Demolition Derby - Wrecked 30 or more cars in city escape. Eradicator - Defeated 100 enemies. Greased Lightning - Cleared Green Hill within one minute. GREEN HILL Restored! - Restored the GREEH HILL stage Gate. Halfway Point - Cleared half the missions. Join the Ranks - Joined the rankings. Jump for Joy! - Found the spring hidden in GREEN HILL Act 1 and reached the goal with a Red Star Ring. Look Both Ways - Reached the goal in CRISIS CITY without being hit by a tornado-carried car. Mad Skillz - Got all custom skills. Mission Accomplished! - Cleared all the missions. Perfect Punisher - Defeated perfect chaos. PLANET WISP Restored! - Restored the PLANET WISP Stage Gate. Red Ring Collector - Got all Red Star Rings. Ring King - Reached the goal without dropping any of the rings you collected in GREEN HILL Act 1. ROOFTOP RUN Restored! - Restored the ROOFTOP RUN Stage Gate. Scrap Metal - Defeated metal sonic. SEASIDE HILL Restored! - Restored the SEASIDE HILL Stage Gate. Secret Sleuth - Got the Red Star Ring located in the hidden room in SEASIDE HILL. Shadow Boxing - Defeated shadow. Shooting Star - Got Rank S in acts three times. Silver Got Served - Defeated silver. SKY SANCTUARY Restored! - Restored the SKY SANCTUARY Stage Gate. SPEED HIGHWAY Restored! - Restored the SPEED HIGHWAY Stage Gate. Sunny side up - Defeated death egg robot. Supersonic! - Cleared a regular stage as Super Sonic. The Byway or the Highway - Got the Red Star Ring located on the shortcut route in SPEED HIGHWAY. The Opening Act - Completed the first stage. Time Attacker - Played Time Attack on all stages. Treasure Hunter - Collected all the Chaos Emeralds. Trickstar - Executed a trick with a seven-step combo or longer. Walk on Air - Cleared SKY SANCTUARY without falling even once. Walk on Water - Cleared CHEMICAL PLANT without entering the water. Walkie Talkie - Chatted with all of Sonic's friends you saved.
After you unlock the original Sonic the Hedgehog, load the game. When Sonic appears on the title screen, hit the following buttons in order: UP, DOWN, LEFT, RIGHT, A. A menu will pop up with all acts selectable.