As far as Sonic games go, it’s surprisingly involved, and its levels have a sense of massive scale that the Genesis games didn’t have. It’s a challenging game, but a great one, and perhaps the pinnacle of the series. There’s also the amazing soundtracks, both the original Japanese one​ and Spencer Nilsen’s U.S. soundtrack that so many Sonic fans are fond of. Not many people played this one because it was on Sega CD, the add-on to the Sega Genesis. There’s a cool story to how this game made it to mobile. Christian Whitehead (also called Taxman and a long-time member of Sonic communities) created the Retro Engine and used Sonic CD to demo it. Eventually, he and his working partner Simon “Stealth” Thomley (also a member of the Sonic community) crossed paths with Sega and they made Sonic CD in the Retro Engine for desktop, consoles, and mobile. The game is ported over to Android. It’s in widescreen, adaptive to multiple screen resolutions, features Tails and Knuckles as playable characters, and has the Japanese and American soundtracks. This is by far the definitive version of the game. The big addition to the game was Hidden Palace. This level is based on cut content from the game only available in leaked beta versions of the game. Accessible through Mystic Cave act 2, this level doesn’t have any significance beyond being a cool Easter egg, but what an Easter egg it is. Oh, and the game’s art, music, and level design are stellar for the series. This classic stands the test of time. The game lacks many of the features that make later games great, such as the two-act zones instead of three like in this game and Sonic’s lack of a spin dash felt limiting. The Christian Whitehead port fixed many of the issues, adding in the spin dash and characters from later in the franchise to make the definitive version of the game. The series improved in later entries, with a better game flow and more fun to be had, but this is still an iconic game for a reason. Sega fixed many issues that were apparent in the first episode of the game (the physics feel like a Sonic game and not a pale imitation) and made a good Sonic game. It feels like a lot of what’s great about this game is imitating the classic games, perhaps to an excessive degree. And the homing attack is a controversial addition to the 2D games. Dimps’ love of bottomless pits in Sonic game design is well on display, too. Regardless, it’s hard to complain about this game too much if you’re a Sonic fan because it’s a fun way to enjoy a legitimate new 2D Sonic game. Do play with a gamepad if possible. Touchscreen controls feel less responsive to classic gamers. There’s a free trial version available if you want to see what the fuss is about. There’s a sequel featuring characters from the Sonic Boom games. On top of that, the console versions underwent significant revamping with a big delay that replaced a couple of levels that otherwise remained in the mobile versions. Several mine cart levels where you tilt back and forth were found in leaked builds of the Xbox 360 version but were left in the mobile versions. It’s not a terrible game, but a severely flawed one that got this new series of games off on the wrong foot. This game is worth picking up mostly as a curiosity, and also because it helps unlock some extra levels in Episode 2 with Sonic CD villain Metal Sonic. It won’t light your world on fire, but at a certain point with the Sonic franchise, “this isn’t terrible” is okay. Remember, the series has seen great lows. There isn’t much to play beyond the Genesis games, but if you have the discs backed up, Reicast and Dolphin can play Dreamcast and GameCube/Wii games, respectively.