Full list of all 49 Sonic Generations achievements worth 1,000 gamerscore. It takes around 20-25 hours to unlock all of the achievements on Xbox 360.
Took no damage from the final boss and cleared the stage.
Got the Red Star Ring by using an Orange Wisp in PLANET WISP Act 2 and reached the goal.
Got all Skills.
Got all collectibles.
Got all Red Star Rings.
Got the Red Star Ring atop the highest spot in ROOFTOP RUN Act 2 and reached the goal.
Got Rank S in all Acts.
Got Rank S in twelve Acts.
Got the Red Star Ring located in the hidden room in SEASIDE HILL Act 1 and reached the goal.
Played Ranking Attack on all stages.
Cleared all the Challenge Acts.
Completed all Challenge Acts featuring Sonic's friends.
Restored the CRISIS CITY Stage Gate.
Restored the ROOFTOP RUN Stage Gate.
Defeated Shadow.
Reached the goal in CRISIS CITY Act 2 without being hit by a tornado-carried cars or rocks.
Got Rank S in seven Acts.
Wrecked 30 or more cars in CITY ESCAPE Act 2.
Got the Red Star Ring located on the shortcut route in SPEED HIGHWAY Act 2 and reached the goal.
Cleared half the Challenge Acts.
Cleared CHEMICAL PLANT Act 2 without entering the water.
Cleared GREEN HILL Act 1 within one minute.
Found the spring hidden in GREEN HILL Act 1 and reached the goal with a Red Star Ring.
Cleared a regular stage as Super Sonic.
Chatted with all of Sonic's friends you saved.
Joined the rankings.
Cleared Sonic Generations.
Collected all the Chaos Emeralds.
Defeated Egg Dragoon.
Pulled off a seven or more trick combo or six trick combo ending in a finishing trick.
Defeated Silver.
Restored the PLANET WISP Stage Gate.
Participated in a 30 Second Trial.
Defeated Metal Sonic.
Defeated Perfect Chaos.
Restored the SEASIDE HILL Stage Gate.
Performed all of Sonic's actions in Act 2.
Restored the CITY ESCAPE Stage Gate.
Got Rank S in three Acts.
Restored the SPEED HIGHWAY Stage Gate.
Defeated Death Egg Robot.
Defeated 100 enemies.
Restored the SKY SANCTUARY Stage Gate.
Restored the CHEMICAL PLANT Stage Gate.
Cleared SKY SANCTUARY Act 1 without falling and losing a life.
Restored the GREEN HILL Stage Gate.
Got Rank S in an Act.
Completed the first stage.
Reached the goal without dropping any of the rings you collected in GREEN HILL Act 1.