Sonic CD released in 1993 for the Sega CD. This game is the sequel to Sonic the Hedgehog 2. This game has seen re-releases on various platforms, as either a part of a collection (Sonic Gems Collection) or the remake made by Christian Whitehead in 2011. I've played both the Gems Collection version and the 2011 remake via PS3. Gems version was good. Had some emulation problems but it ran well. However, the version I will be reviewing is the 2011 version for PS3.
The plot begins with Sonic travelling to Never Lake to witness a planet called Little Planet; which appears every December. However, Eggman who is up to no good as usual tethers the planet and creates his own fortress there. Once again, Sonic is tasked with stopping Eggman and his nefarious plans.
Sonic CD in terms of gameplay is the same gameplay from the two games prior; go fast, get high scores and beat Eggman. There is a new game wide mechanic in the form of time travelling. No, it's not like how Sonic 2006 handled time travelling (thank god). There are posts that have Past, and Future on them. touching them and then maintaining a certain speed will have Sonic travel to the past or future. This plays a part in obtaining the Good Ending, in which you have to travel to the past, break the machines that are polluting it to get a Good Future in that Act. This must be done for all Acts in the game. You can also get the Time Stones by entering a Special Stage via 50 rings to obtain the Good Ending that way, which is a nice alternative for those who aren't bothered in finding the machines.
There are now two types of the soundtrack; The Japanese version and the US version. You can choose which type you prefer in the main menu for the remake, but do be warned that it will lock to that soundtrack once you start the game. I've only listened to the US soundtrack and might I say, the OST is great! Favourites like Wacky Workbench to the Credits/Main theme of the game comes to mind.
Overall, while it may not be my favourite game in the series, Sonic CD provides that same level of fun that a Sonic game should have. It mechanically plays well, except for collision detection issues, which are minor but do cause the odd death. I highly recommend you play the 2011 remake if you haven't played it yet, as it is without a doubt the definitive version of Sonic CD. It also lets you play as Tails too when you beat the game once, so that's a plus.