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