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