Here is the full list of all 48 Sonic Forces achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Collected a total of 100,000 rings. (All Rings held at the end of the stage will be counted.)
Collected all Wispons
Collected all parts
Achieved highest honors with all races
Completed all Challenge Missions
Collected a total of 50,000 rings. (All Rings held at the end of the stage will be counted.)
Defeated 10,000 enemies
Collected 500 parts
Cleared all EX Stages
Collected all Silver Moon Rings
Collected all Number Rings
Collected all Red Star Rings
Completed 10 Daily Missions
Made it into the rankings
Collected 30 Wispons
Collected Silver Moon Rings three times
Defeated 5,000 enemies
Collected Number Rings three times
Created your second Avatar
Completed 10 SOS Missions
Collected a total of 10,000 rings. (All Rings held at the end of the stage will be counted.)
Completed 5 Daily Missions
Equipped a part in every slot
Cleared all Secret Stages
Achieved a soldier's highest honor
Collected all Silver Moon Rings in Shadow's Story.
Collected all Number Rings in Shadow's Story.
Collected all Red Star Rings in Shadow's Story.
Restored peace to the world
Defeated Infinite
Turned the tide of the conflict
Completed 5 SOS Missions
Collected 10 Wispons
Utilized the Rental Avatar function
Drove off Infinite again
Defeated 1,000 enemies
Used the Closet
Collected 100 parts
Completed your first SOS Mission
Liberated a world
Drove off Eggman
Collected 50 parts
Drove off Infinite
Defeated Zavok
Changed Wispons for the first time
Completed 3 Daily Missions
Created an Avatar
Cleared Stage 1