Full list of all 12 Sonic the Hedgehog 4 - Episode I achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Defeat the final boss and view the ending.
Defeat a boss for the first time.
Clear SPLASH HILL ZONE, ACT 1.
Acquire a Chaos Emerald.
Defeat 1,000 enemies.
Clear all Acts as Super Sonic.
Upload your recorded scores and clear times for all stages.
Collect all the Rings in 'Special Stage 1' and Clear the stage.
Build up 99 or more extra lives.
Acquire all seven Chaos Emeralds.
Clear SPLASH HILL ZONE ACT 1 in less than a minute.
Clear the E.G.G. STATION ZONE without taking any damage.