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