It's about time.
Sonic CD could never catch a break. Developed by the remnants of Sonic Team after Yuji Naka went to the United States to produce Sonic 2, released on a peripheral that never caught fire, and left out of almost every Sonic the Hedgehog collection or rerelease in the years (decades!) that followed, luck never seemed to be on the side of the second* weirdest Sonic game to blaze out of the 90's.
So how ironic is it that Sonic CD is the recipient of the finest port of any of Sega's Genesis-era Sonic games? Backbone Entertainment, whom handled Sonic's Genesis Collection as well as the Live Arcade releases, coughed up lazy ports and couldn't even be bothered to get Sonic and Knuckles to play nicely with Sonic 2 and 3. This port of Sonic CD, on the other hand, was forged by a fan as a proof of concept and later employed by Sega for a commercial release. Christian "Taxman" Whitehead built Sonic CD's "retro engine" to not only properly emulate the Sega CD classic, but also with sixty frames a second at 1080p with proper widescreen support. Tender loving care isn’t a concept often applied to reproducing an almost twenty year old game, but take one look at Sonic CD running on a nice television and you’ll undoubtedly agree.
Taxman's gift didn't just make Sonic CD easier on our 2011 eyes, it also made the game fundamentally better than one might remember. Of particular benefit were the special stages. Background rotation and scaling were neat for early stabs at three dimensional play, but made a mess of perspective. Hunting down UFO's, the primary task in the special stages, was always a chore because you could never quite tell when exactly you needed to jump to make contact. Now with a stable frame rate and a crisper picture, it's substantially easier for Sonic to wreck shop and collect all of the Time Stones.
A few extra bells and whistles also come attached to the interface. Amenities consistent with modern game design, such as multiple save files, a few graphical filters, a couple of unlockable extras (including the ability to play as Tails), and slick new user interface included. The best, and the one that was paramount to any future release of Sonic CD, was the ability to select either the North American or original Japanese soundtrack. While I'm partial to the default American tunes from my youth, I can't deny that the Japanese tracks are objectively better. In fact, Sonic CD's original soundtrack might be the most varied and all around interesting of any Sonic game. Wacky Workbench's bad future waits almost ninety seconds before it blows its top, and the vocal samples in Stardust Speedway remind us of what it was like when the existence of uncompressed audio was actually shocking. I wish there would have been an option to switch tracks on the fly rather than a menu before the game is started, but it's an omission I can live with.
Of course there's also the little part where you have to decide whether or nothing you would enjoy playing Sonic CD, which typically runs the gamut from interesting to divisive. Developed under the parameters of a universe where Sonic 2 didn't exist, it bears a greater resemblance to the claustrophobic, catastrophic bowels of the original Sonic the Hedgehog rather than the proper sequels we all know and love. Typical criticisms of Sonic CD include the levels having a slapdash, almost fan-made feel to them. The aforementioned Wacky Workbench is a testament to this, as certain portions will literally loop over and over until you get it right. The game is chalk full of time wasting dead ends, maliciously placed badniks, and general lack of cohesion.
And time travel. Each of Sonic CD's seven zones features four different zones for each of its two main acts. Sonic starts in the present, but can go to the past to destroyed one of Dr. Robotnik's robot machines. Sonic can then travel to the "good future" that's absent of any enemies and finish out the act. If Sonic fails to destroy the machine or simply skips right to the future, he'll be in the "bad future." Slightly reworked level design and music along with different tile sets differentiate each time period. This sort of explains the seemingly random nature of each level's construction, as Sonic Team had to account for a myriad of possibilities regarding where and when Sonic would wind up in the level, not to mention creating more back-travel friendly schemes.
The caveat is Sonic can only time travel by passing through "past" or "future" sign posts, and then building up and maintaining speed for five or so seconds. This is often easier said than done, as Sonic CD, while featuring a handful of genuine speed loops, often makes time travel a chore for new players. It's worth noting that it's totally possible to ignore time travel completely and attempt to blast through Sonic CD like a normal Sonic game, but in doing so you'd miss the nuance and texture that transformed Sonic CD from a disorganized Sonic game into a genuine cult classic.
Sonic CD also comes with a smart price; $5. $10 would have been justifiable given the amount of work than went into making this port better than the original, but $5 is a sweet spot that counteracts Sonic CD's divisive nature with an appealing price point. It's incredibly low risk, and easy to pull the trigger for fans and newcomers alike.
*First is and always will be Chaotix, folks.