This is the complete list of unlockable achievements in Sonic Generations for the Xbox 360.
There are twenty-seven secret achievements you can unlock that are listed at the bottom.
A 30-Second Test (20) – Participate in a 30 Second Trial
Action Hero (10) – Perform all of Sonic’s moves in Act 2
All Stages Cleared! (50) – Clear Sonic Generations
Big Bang (50) – Get Rank S in all Acts
Blazing Meteor (30) – Get Rank S in seven Acts
Blue Comet (40) – Get Rank S in twelve Acts
Bonds of Friendship (10) – Complete all Challenge Acts featuring Sonic’s friends
Bright Star (15) – Get Rank S in an Act
Eradicator (15) – Defeat 100 enemies
Greased Lightning (10) – Clear GREEN HILL Act 1 within one minute
Halfway Point (30) – Clear half the Challenge Acts
(Hedge)Hogging It All Up! (50) – Get all collectibles
Join the Ranks (20) – Join the rankings
Mad Skillz (30) – Get all Skills
Mission Accomplished! (30) – Clear all the Challenge Acts
Red Ring Collector (30) – Get all Red Star Rings
Ring King (15) – Reach the goal without dropping any of the rings you collected in GREEN HILL Act 1
Shooting Star (20) – Get Rank S in three Acts
The Opening Act (10) – Race through the first stage
Time Attacker (30) – Play Ranking Attack on all stages
Trickstar (10) – Pull off a seven or more trick combo or six trick combo ending in a finishing trick
Walkie Talkie (10) – Chat with each of Sonic’s friends you have saved
Here are the twenty-seven secret achievements you can unlock in the game.
A Quick Breather (10) – Got the Red Star Ring atop the highest spot in ROOFTOP RUN Act 2 and reached the goal
Boom Boom Dragoon (30) – Defeated Egg Dragoon
Can’t Touch This (30) – Took no damage from the final boss and cleared the stage
CHEMICAL PLANT Restored! (15) – Restored the CHEMICAL PLANT Stage Gate
CITY ESCAPE Restored! (15) – Restored the CITY ESCAPE Stage Gate
Color Power! (10) – Got the Red Star Ring by using an Orange Wisp in PLANET WISP Act 2 and reached the goal
CRISIS CITY Restored! (15) – Restored the CRISIS CITY Stage Gate
Demolition Derby (10) – Wrecked 30 or more cars in CITY ESCAPE Act 2
GREEN HILL Restored! (15) – Restored the GREEN HILL Stage Gate
Jump for Joy! (10) – Found the spring hidden in GREEN HILL Act 1 and reached the goal with a Red Star Ring
Look Both Ways (10) – Reached the goal in CRISIS CITY Act 2 without being hit by a tornado-carried cars or rocks
Perfect Punisher (25) – Defeated Perfect Chaos
PLANET WISP Restored! (15) – Restored the PLANET WISP Stage Gate
ROOFTOP RUN Restored! (15) – Restored the ROOFTOP RUN Stage Gate
Scrap Metal (20) – Defeated Metal Sonic
SEASIDE HILL Restored! (15) – Restored the SEASIDE HILL Stage Gate
Secret Sleuth (10) – Got the Red Star Ring located in the hidden room in SEASIDE HILL Act 1 and reached the goal
Shadow Boxing (25) – Defeated Shadow
Silver Got Served (30) – Defeated Silver
SKY SANCTUARY Restored! (15) – Restored the SKY SANCTUARY Stage Gate
SPEED HIGHWAY Restored! (15) – Restored the SPEED HIGHWAY Stage Gate
Sunny Side Up (20) – Defeated Death Egg Robot
Supersonic! (20) – Cleared a regular stage as Super Sonic
The Byway or the Highway (20) – Got the Red Star Ring located on the shortcut route in SPEED HIGHWAY Act 2 and reached the goal
Treasure Hunter (20) – Collected all the Chaos Emeralds
Walk on Air (20) – Cleared SKY SANCTUARY Act 1 without falling and losing a life
Walk on Water (10) – Cleared CHEMICAL PLANT Act 2 without entering the water