If you liked this
Games like Sonic: Dark Abyss
If you finished Sonic: Dark Abyss, the closest matches are 5 Nights At Grek's Hotel, Sonic the Hedgehog: Editable ROM EYX, Sonic Classic 2, Sonic.exe The Disaster 2D Remake and Sonic Classic. All 10 share its platform genre and are ranked by how closely their themes and modes overlap.
