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