Overview:

-Estimated achievement difficulty: 4
-Offline: 46 (930 )
-Online: 3 (70 )
-Approximate amount of time to 1000: 15-20 Hours
-Minimum number of playthroughs needed 1 (plus replaying levels/challenges)
-Number of missable achievements? None!
-Do cheat codes disable achievements? None!
-Does difficulty affect achievements? None!
-Glitchy achievements? Zone Restored and Eradicator (see introduction)
-Unobtainable achievements? None!
-Extra equipment needed? None!
-Avatar Awards: 6 (3 for Males and 3 for Females)

Introduction
Welcome to the Sonic Generations Achievement Guide! Sonic Generations features both Classic and Modern Sonic to play as. Each Zone has two acts. In Act 1 you play as Classic Sonic which plays just like Genesis Sonic Games and Act 2 you play as Modern Sonic which plays like the newer Sonic Games. This game has a total of 49achievements for 1000 . The majority of these achievements are not difficult, but some will require patience. So just enjoy playing the game and have fun!

The Zone Restored achievements and Eradicator achievements are slightly glitchy. For some people they don't unlock when they should. Unfortunately, if this happens to you the only way to get the achievements is to delete your save file and start the game over.

Step 1: Beat the Story
Just have fun playing the game! You will earn the 18 storyline achievements for 365 and  the following 3 achievements while playing the game normally:

  • Eradicator
  • Action Hero
  • Walkie Talkie

Note: To earn the Walkie Talkie achievement, talked to all of sonic friends after Restoring Planet Wisp

Step 2: Complete the Challenges
Once you beat the Final Boss, go back and complete all the challenges. There are 45 for Classic Sonic and 45 for Modern Sonic. When you beat a challenge collect the artwork or song, by hitting the bell and touching the music note. You will unlock the following 3 achievements for 70 :

  • Bonds of Friendship
  • Halfway Point
  • Mission Accomplished!

Step 3: Collecting the Red Rings
After you finish all challenges, go back to each stage and collect all five red rings in each stage. Once you collect all the Red Rings you should have every collectible. At this Point you should have enough Points to buy every Skill from the shop to unlock the Mad Skillz achievement.

While going for the Jumping for Joy achievement, I would suggest equipping the Supersonic Skill Set to classic Sonic, and finishing the level as Supersonic so you can earned the Supersonic! achievement too.  You will earn the following 9 achievements for 190

  • Red Ring Collector
  • Mad Skillz
  • (Hedge)Hogging it All Up!
  • Supersonic!
  • Jump for Joy!
  • The Byway or the Highway
  • Secret Sleuth
  • A Quick Breather
  • Color Power!

Step 4: Ranking Attack
At the Main Menu, go to Xbox live and go to 30 Second Trail, complete one to get an easy achievement. Next go to Ranking Attack, and set a time in every stage for both Classic Sonic and Modern Sonic.

You will unlock Join the Ranks, A 30-Second Test, and Time Attacker!

Step 5: S-Ranks/Level Specific achievements
Now will be the time to get any level Specific achievement you are missing, S-Rank any stages you haven't done yet and beat the Final Boss without getting hit. Refer to the guide below for help and you'll earn your final 13 achievements and 270 .

Conclusion
If you've followed the guide and roadmap to this point, you should have the full 1000 in Sonic Generations. Congratulations!

[x360a would like to thank Fullmetalx07 for this roadmap]

Sonic Generations Achievement Guide

Show completed achievements
Show secret achievements

There are 49 achievements with a total of 1000 points

  • Race through the first stage.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Clear Sonic Generations.

    There are three levels to complete in the Genesis Era and there are Green Hill Zone, Chemical Plant Zone, and Sky Sanctuary. Once you complete all three Zone, the challenges acts will unlock. you need to beat one challenge from each stage in order to collect the boss key. You need to collect all three in order to face the Death Egg Robot. Once you collect all 3 keys, challenge Metal Sonic to a fight; beat him in order to get your first Chaos Emerald.

    Once you beat the boss, you will unlock the Dreamcast Era Stages. Beat both Act 1 and 2, fight Shadow to claim his Chaos Emerald and beat at least three challenges. The Boss in the Dreamcast Era Stage is Perfect Chaos; Beat him to unlock the Modern Era Stages.

    The fifth Chaos Emerald is just given to you; Same thing here, beat all the three levels to get a Chaos Emerald. Challenge Silver to fight to get his Chaos Emerald and then fight the Egg Dragoon to get seventh and Final Chaos Emerald.

    In order to fight the Final Boss, you need to collect all seven Chaos Emeralds. One 1 is given to you, three are from Boss fights and the other three are from the Rival fights. The final boss is Time Eater, beat him to unlock Super Sonic skill set and to see the ending of Sonic Generations!

  • Clear GREEN HILL Act 1 within one minute.

    Refer to the video below. The achievement will pop in the ranking screen.

  • Get Rank S in an Act.

    Refer to Big Bang.

  • Get Rank S in three Acts.

    Refer to Big Bang.

  • Get Rank S in seven Acts.

    Refer to Big Bang.

  • Get Rank S in twelve Acts.

    Refer to Big Bang.

  • Get Rank S in all Acts.

    In order to earn S Rank in an Act, you have to get an A rank and get a Perfect Bonus. A Perfect Bonus is awrded completing the level without losing a life. You need to earn at least 50,000 in order to get an A rank, however there no way to tell how many points you have until you complete the level.

    Note: Getting an S-Rank on any of the Rival, Boss, or Challenge acts does not count towards this achievement. It also must be done in the story mode, getting S-rank in Ranking mode will not count.

  • Pull off a seven or more trick combo or six trick combo ending in a finishing trick.

    Refer to the video below. This can only be done as Modern Sonic.

  • Defeat 100 enemies.

    This should come with natural story progression. If not, just target enemies while going for Big Bang.

  • Reach the goal without dropping any of the rings you collected in GREEN HILL Act 1.

    Just collect at least one ring, and then don't get hit by any enemies or spikes. Just take your time and this shouldn't be an issue. Refer to the video below if you need more help.

  • Perform all of Sonic's moves in Act 2.

    Story-related, can't be missed.

    You need to perform three of Sonic's moves. The three moves are the stomp, the lightspeed dash, and the wall jump. You can do the stomp move any time during Act 2, the first time you can use the lightspeed dash is in Speed Highway Act 2, and the first time you can do the wall jump is in Green Hill Zone Act 2, but if you miss or can't find then you can do it in, Seaside Hill Act 2.

    • To perform the stomp move hit to jump and while in the air to stomp.
    • To perform the lightspeed dash hit while there is a line of rings in front of you.
    • To perform the wall jump, you need a wall panel to be on the wall (obliviously) and hit to jump on the wall panel and hit again to jump off it.
  • Complete all Challenge Acts featuring Sonic's friends.

    Refer to Mission Accomplished.

  • Chat with each of Sonic's friends you have saved.

    You need complete both Act 1 and 2 of Green Hill Zone, Chemical Plant Zone, Sky Sanctuary Zone, Speed Highway, City Escape, Seaside Hill, Crisis City, Rooftop Run, and Planet Wisp to save all of Sonic's friends. Once you have done this then, go to each of Sonic's friends and press up on the to talk to them.

  • Join the rankings.

    Refer to Time Attacker!

  • Participate in a 30 Second Trial.

    From the main menu, go to Xbox Live and select 30 Second trail. A 30 Second trail is seeing how far you get in a level within 30 seconds. Select any level, the easiest will be Green Hill Zone Act 1. Once the 30 secs are up the achievement will unlock.

  • Get all Skills.

    First, make sure you get all red star rings in the required acts. This will unlock skills and automatically give them to you. Next, do all of the challenges. This will allow you to purchase more skills from the shop. Then complete the game with all seven Chaos Emeralds. All of the skills will now be purchaseable in the shop, but it will require a fair amount of rings, so make sure you save your money.

  • Get all collectibles.

    Refer to Mission Accomplished! and Red Ring Collector.

  • Play Ranking Attack on all stages.

    From the main menu, go to Xbox Live and select Ranking Attack. Complete all levels of both Act 1 and 2 to get the achievement. You can finish with any time as long as you complete the level.

  • Get all Red Star Rings.

    In each Zone, there are ten Red Star Rings to collect, five for classic Sonic and five for modern Sonic. They are usually hidden in each zone, some of them of are easy to get, some of them are hard.

    Each Red Star Ring, you collect will give you an artwork or a Song. Once you collect all 5 Red Rings for a Zone, you will earn a skill.

  • Clear half the Challenge Acts.

    Refer to Mission Accomplished!

  • Clear all the Challenge Acts.

    There are 90 Challenge Acts in the game; 45 for Classic Sonic and 45 for Modern Sonic. Each Zone has total of 10 Challenges with five for Classic Sonic and five for Modern Sonic. While completing the Challenge Acts, you will unlock the Bonds of Friendship achievement.

    Each time you complete an challenge act, hit the bell and hit the music note to get an artwork or a song.

 

Secret achievements

  • Restored the SKY SANCTUARY Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the SPEED HIGHWAY Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the CITY ESCAPE Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the GREEN HILL Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the CHEMICAL PLANT Stage Gate.

    Story-related, Can not be missed.

    See All Stages Cleared!

  • Restored the PLANET WISP Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the SEASIDE HILL Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the CRISIS CITY Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Restored the ROOFTOP RUN Stage Gate.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Collected all the Chaos Emeralds.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Defeated Shadow.

    Story-related, can't be missed. Refer to All Stages Cleared!

    If you're having problems with the boss battle, refer to this video: 

  • Defeated Silver.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Defeated Metal Sonic.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Defeated Perfect Chaos.

    Story-related, can't be missed. Refer to All Stages Cleared!

    If you're having problems with the boss battle, refer to this video: 

  • Defeated Egg Dragoon.

    Story-related, can't be missed. Refer to All Stages Cleared!

  • Defeated Death Egg Robot.

    Story-related, can't be missed. Refer to All Stages Cleared!

    If you're having problems with the boss battle, refer to this video: 

  • Took no damage from the final boss and cleared the stage.

    This is greatly complicated by the fact that you're not allowed to take damage. Refer to the video below.

  • Got the Red Star Ring atop the highest spot in ROOFTOP RUN Act 2 and reached the goal.

     

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Got the Red Star Ring by using an Orange Wisp in PLANET WISP Act 2 and reached the goal.

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Cleared a regular stage as Super Sonic.

    In order to clear a regular stage as Super Sonic, you need the Super Sonic skill. To get it you have to beat the final boss and buy the skill from the shop. Equip it and enter any stage, the easiest will be Green Hill Zone Act 1. Collect 50 rings and hit to transform into Super Sonic. Finish the stage and the achievement is yours.

  • Cleared SKY SANCTUARY Act 1 without falling and losing a life.

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Wrecked 30 or more cars in CITY ESCAPE Act 2.

    You have to hit 30 cars while on your skateboard at the beginning of the lvel. Refer to the video below. The achievement will unlock in the ranking screen.

  • Got the Red Star Ring located in the hidden room in SEASIDE HILL Act 1 and reached the goal.

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Reached the goal in CRISIS CITY Act 2 without being hit by a tornado-carried cars or rocks.

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Cleared CHEMICAL PLANT Act 2 without entering the water.

    Refer to the video below. The achievement will unlock during the ranking screen.

  • Found the spring hidden in GREEN HILL Act 1 and reached the goal with a Red Star Ring.

    Refer to the video below. The achievement will unlock in the ranking screen.

  • Got the Red Star Ring located on the shortcut route in SPEED HIGHWAY Act 2 and reached the goal.

     

    Refer to the video below. The achievement will unlock in the ranking screen.