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