Is Sonic CD on Steam?

No. Sonic CD is not distributed on Steam, so there is no Steam Charts or SteamDB player count for it. Its live popularity is tracked here via Twitch viewership instead.

What platforms is Sonic CD on?

Sonic CD is available on PC (Microsoft Windows), Sega CD, Amazon Fire TV, Xbox Series X|S, PlayStation 3, PlayStation 4, Ouya, Linux, Windows Phone, Android, iOS, PlayStation 5, Xbox 360, Xbox One, Nintendo Switch.

When did Sonic CD release?

Sonic CD was first released on September 23, 1993.

Sonic CD

Sep 23, 1993PlatformPC (Microsoft Windows)Sega CDAmazon Fire TVXbox Series X|S PlayStation 3

Sonic CD — frequently asked questions

Is Sonic CD on Steam?: No. Sonic CD is not distributed on Steam, so there is no Steam Charts or SteamDB player count for it. Its live popularity is tracked here via Twitch viewership instead.
What platforms is Sonic CD on?: Sonic CD is available on PC (Microsoft Windows), Sega CD, Amazon Fire TV, Xbox Series X|S, PlayStation 3, PlayStation 4, Ouya, Linux, Windows Phone, Android, iOS, PlayStation 5, Xbox 360, Xbox One, Nintendo Switch.
When did Sonic CD release?: Sonic CD was first released on September 23, 1993.

About Sonic CD

Sonic travels to the distant shores of Never Lake for the once-a-year appearance of Little Planet - a mysterious world where past, present, and future collide through the power of the Time Stones that lie hidden within it. Sonic arrives only to find the once beautiful world imprisoned beneath a twisted metallic shell. His arch-nemesis, Dr. Eggman, has come for the Time Stones and with them, will soon have the power to control time itself! In order to put an end to Dr. Eggman’s nefarious schemes, Sonic must use the power of Little Planet to travel through time; breaking Dr. Eggman’s hold over the future by destroying his machines in the past and recovering the missing Time Stones!

Summary via IGDB.

Sonic CD on Wikipedia

Sonic the Hedgehog CD is a 1993 platform game developed and published by Sega for the Sega CD. As Sonic the Hedgehog, the player attempts to protect an extraterrestrial body, Little Planet, from Doctor Robotnik. Like other Sonic games, Sonic runs through themed levels while collecting rings and defeating robots. Sonic CD introduces time travel as a game mechanic. By traveling through time, players can access different versions of stages, featuring alternative layouts, music, and graphics. Sonic CD introduced the characters Amy Rose and Metal Sonic.

Source: Wikipedia (text under CC BY-SA 4.0).