Full list of all 25 SEGA Genesis Classics achievements worth 1,000 gamerscore. It takes around 8-10 hours to unlock all of the achievements on Xbox One.
Sonic Games - Collected 500 rings
Shinobi 3 - Earnt a Shinobi bonus (complete a level without throwing a shuriken)
Dynamite Headdy - Defeated the Robo Collector
Played 50 games
Played 20 games
Space Harrier 2 - Reached a score of 5,000,000
1 Challenge completed
Toejam and Earl - Danced the Hula
Alien Soldier - Used 4 different weapon modes in one session
Golden Axe - Used magic when no enemies are present
Columns - Gained a high score of at least 5000 on easy
Sonic The Hedgehog - Collect all 6 Chaos Emeralds
Sonic Spinball - Collect all 3 Chaos Emeralds
Toejam and Earl - Find the secret island
Golden Axe 2- Kill 25 enemies by throwing/knocking them off the environment in a single play through
Golden Axe 3 - Max out your magic
Sonic 2 - Finish Emerald Hills with 5 lives
Shining Force - Make it to Alterone
Complete 10 challenges
Streets of Rage - Get to the final boss without using a continue
Alex Kidd - Win 50 Games of Rock, Paper, Scissors
Shadow Dancer - Complete the first two stages without using magic
Streets of Rage 3 - Finish the game
Golden Axe Games - Collect 200 magic
Complete all challenges