Playing Sonic CD on the iPad recalls the glory years of the Genesis releases; four great games that were effectively simple, yet complex to master. While this game may be unfairly segregated for originating on the ill-fated Sega CD, it is rightfully a part of the blue hedgehog's early legacy.
Animated cut scenes detail the opening and endings of the game (which differs based on whether Sonic collects the seven 'time stones'), which sets CD apart from others of its ilk. There is such a diverse palette here that each new area offers something new, yet all the Sonic staples - springs, spikes, item monitors - remain accounted for. Controls are replicated simply on the iPad via a D-Pad and Jump button on the bottom of your screen; these respond well, even to sloppy contact, and they never get in the way of the action (though there may be a small learning curve for those accustomed to a classic controller).
A charming blend of visuals from the original classic and gameplay advances from the sequel, CD's development history is surrounded by speculation and Sega's own corporate affairs at the time. What is noteworthy about CD now, in 2011, is that despite being an early entry in the franchise it features a gameplay mechanic that perhaps remains the series' most innovative. Utilising time travel, Sonic can move back and forth between past, present and future within each level and change the course of time. This results in differences that alter the challenge, for example increasing difficulty in a 'bad future' where neglected machinery presents a greater threat. This introduces the player to numerous variations on each and every zone, adding a tremendous amount of replay value. The boss battles are amongst the most memorable of the side-scrollers; there's a good reason why the climax of the penultimate level, a nerve-wracking race over slopes and spikes against Sonic's own doppleganger, was recreated in the recent 'Sonic Generations'.
Having been re-released across multiple platforms by a Sega promoting the game's events as a prequel to 'Sonic the Hedgehog 4', there is no excuse not to have played this terrific entry in Sega's flagship property.
9/10
