One wonders just how fresh Sonic CD might have been had it been the first game in the Sonic the Hedgehog series. The problem with Sonic CD isn't that it doesn't withstand a gorging by the Time Monster; in fact it stands up very well against time's ravages. Sonic CD's problem is a little bit more unique than that: It doesn't hold up to its own place in the series. Released between the second and third games for the Genesis, the Blue Blur's only appearance on the Sega CD is filled with experiments, one-time features, and odd gimmicks which are usually reserved for the first game in a new and potentially ongoing flagship series. Many gamers claim Sonic CD is the most essential component of Sonic's core games during the 16-bit era. The truth is that of the core Sonic games, only Sonic 3D Blast is less essential than Sonic CD, and even that contest is very debatable. Sonic CD feels like a series of scenes on a DVD special edition which were edited out of the primary feature.
Sonic Team had no part of the development of Sonic CD, and so Sonic CD stands out among the 16-bit Sonic games in some very unique ways. Many of the little differences feel like they were experimental features which would have gradually evolved later in the series or been thrown out. The levels, for instance, are officially called "rounds" in Sonic CD instead of "zones," as they are in other Sonic games. The rounds are all completed in three acts, as opposed to the usual two in every Sonic game after Sonic 1. The third act is specifically a boss act, where all you do is find and fight Dr. Robotnik. In Sonic CD, you set out to rescue plants. When enemies are defeated, they produce seeds which visibly fall to the ground and sprout flowers. At the end of every level, you smash a giant mechanical pod instead of an animal trap. Sonic CD is the only Sonic game in which you rescue a princess, who you actually see kidnapped by Metal Sonic at the beginning of Collision Chaos and actually rescue at the end of Stardust Speedway. (The princess in Sonic CD is named Sally, but she doesn't look anything like the strong-willed freedom fighter bearing her name in the classic ultradark Saturday morning TV show. Sonic CD's Princess Sally is actually an early design of the character who would later become Amy Rose.) The plot excludes Chaos Emeralds and instead features Time Stones. While time travel factors into the gameplay, the acts in Sonic CD are still the shortest in the entire series.
The plot of Sonic CD revolves around a place called Little Planet, which holds special gems which control the passage of time for the dinosaurs. Naturally, Dr. Robotnik caught wind of the special powers of these stones and is trying to harness that power for his own nefarious purposes. He launches Metal Sonic to kidnap Princess Sally and use her as bait to keep Sonic off his tail. For all the fuss made about Metal Sonic, he doesn't play a huge role anywhere in this game or anywhere in the whole Sonic series in any console generation. I see other reviewers write about Metal Sonic as if he is the bringer of the apocalypse, but he is utterly insignificant. Shadow the Hedgehog, who was introduced in the Dreamcast games, plays more of a role in the Sonic series than Metal Sonic. But I digress. The manual of Sonic CD fails to say this, but part of the gameplay apparently revolves around trying to keep Sonic in the past as much as possible in order to get the best ending.
The level designs find a balance between inspired and infuriating. After the typical Sonic the Hedgehog game forest entry level – known as Palmtree Panic in this game – Sonic CD takes you through one level which looks like a bare-boned version of the Casino Night Zone from Sonic 2 (Collision Chaos), another level which bares a resemblance to the Star Light Zone from the original Sonic game (Stardust Speedway), and ends with the regular big-machine level (Metallic Madness). Along the way, you'll travel through the Obligatory Water Level in which Sonic faces serious danger of drowning (Tidal Tempest), a world with a ton of conveyor belts (Quartz Quadrant), and a level in which the floor itself bounces you high into the air if you touch it while it flashes (Wacky Workbench). All of these are three-act levels. In the first two acts of each, you can bounce around between past, present, and future more often than Marty McFly. In the third act, you visit the future, where you fight Dr. Robotnik. Although you can exit an act in any time period, you start the following act in the present if it's a non-boss act.
While I was a constant failure in the more advanced forms of math, I do realize this layout has the potential for nine boards per round for seven rounds. That's 63 boards. Subtract 14 because you can't time travel in the boss acts and you still get a grand total of 49 boards. This should be much more impressive than it is. Unfortunately, the aesthetics of the rounds change very little when you travel from one time period to another. Time travel does things to the aesthetics which are so minute they're barely noticeable in most rounds, though it can raise or lower the water level in Tidal Tempest. The big change which comes through time travel is in the graphics. When you visit the past, you're surrounded by woodland and plant life. The present brings a 50/50 mix between nature and machine. The future paints a grim picture of a Little Planet dominated entirely by robots. Past, present, and future all have their own music as well.
I like the concept of time travel, but not only are there problems with aesthetic variations of time periods, the actual act of traveling through time also poses problems of its own. To leap to another time period, you have to hit a lamppost with the word "past" or the word "future" on it. Once you activate the time lamppost, you then have to crank Sonic's speed up to a level which would overheat the DeLorean. When you get Sonic going fast enough, he makes the time jump. It's simple in theory but hard in execution because Sonic takes a bit too long to make his jump, and you're subjected to a lot of speed-breaking obstacles which can stop him completely. There are other times where you'll reach the necessary speed to jump through time only to hit another time lamppost and travel to the period written on the lamppost you just hit. If you get trapped on a flywheel, Sonic will reach his time jump speed automatically, even if you're not trying to make trip to another time period.
The level designs are very unusual for a Sonic game. The end-of-act time bonus will end up being fairly large in most cases because the acts are so short you'll always reach the end of the act in less than two minutes even if you mosey along and smell all the roses. But while the acts don't contain a whole lot on a horizontal scale, on a vertical scale the Sears Tower would crane its neck to stare up at them. There are some acts which just seem to move endlessly up and down. This makes the individual acts more interesting because it will take several playthroughs for you to take every path available in every act. Almost every time I play, I discover a path I haven't seen yet. The downside of stratospheric acts is that getting to a different path requires an overt reliance on springs, and this means having to make leaps of faith and surrendering a good chunk of control over Sonic.
Perhaps due to the shortness of the acts, springs are also one of the most prominent obstacles in the game. This isn't the first Sonic game to feature wall springs as basic hinderers of progress, but the guiding philosophy of Sonic CD's design team seems to be "when in doubt, use a spring!" Obstacles which cause Sonic to bounce are a major part of many rounds. Collision Chaos is littered with endless fields of springs and Wacky Workbench has a flashing floor on the bottom which causes Sonic to soar if he touches it. Stardust Speedway, Sonic CD's only true speed round, has ledges with a number of springs and every time you think you've got a good run gaining momentum, BAM! Sonic flies off another spring. The siren rages when Sonic's developers can't get the speed round right. Perhaps just for irony, you have two moves which allow you to build up Sonic's speed before charging off into the sunset (where another spring will probably toss you back): One is your basic Spin Dash Attack, a staple in every Sonic game since Sonic 2. The second is the Super Peel Out, which performs the very same function as the Spin Dash Attack without the bonus of invulnerability. I'm at a loss figuring out why the Super Peel Out exists.
The boss fights in Sonic CD are unique to the series. The common complaint is that they're too easy, and this is true. They're possibly the easiest in the series. But they're weird concoctions; the boss fights are not so much about hitting Dr. Robotnik as they are about fighting for the hits. A couple of rounds involve chasing the doc through a maze. In Quartz Quadrant, you simply have to run at him until his machine wears out. All of them present their own twists and challenges, and when you reach Stardust Speedway, you're treated to one of the greatest boss fights ever: A footrace against Metal Sonic. The bonus stages, where you win the Time Stones, are love it/hate it designs. You run through the bonus round, jumping to destroy flying saucers while avoiding obstacles. While this can be fun, getting the timing for when to make a jump is a real pain. There's a sharp learning curve involved in the bonus stages, and even after you figure them out, they can still frustrate.
The graphics in Sonic CD are Sonic games seen through an acid trip lens. Aside from an opening intro, there isn't a whole lot here which couldn't be done on the Genesis. But the colors are brighter than their cartridge counterparts, and the graphics just seem to leap off the screen and shout "BOO! Look at me!" The power of the Sega CD means there's greater variety in the evil robots you'll be facing. The past, present, and future all have different looks. The past always comes out as the most colorful and psychedelic-looking of the three, and the robot-dominated future looks bleaker than the future-after-Lavos landscape from Chrono Trigger. The animation is barely noticeable, but if you care about animation is a Sonic game the designers probably screwed up anyway. The designs are terrific.
Sonic CD has a classic soundtrack. The three time periods have their own unique themes, with the most lively again coming from the past and the bleakest again from the future. The music is a good effort, but it doesn't live up to its reputation. The music is good but it's also very tiny-sounding, and so it simply sits in the background massaging the rounds instead of surrounding you with that great Sonic atmosphere and drawing you into the game. It isn't the best music in the series, either; Sonic 2, with its memorable influences of b-movies, bluegrass, hot jazz, and middle eastern music is far superior to Sonic CD's themes.
The gameplay is typical Sonic the Hedgehog. You run fast, and speeding up is harder on hills than it is on flatlands and descending inclines. You have two moves which help Sonic build speed, which are nice even though one is totally unnecessary. Unfortunately, when you use either of those moves, you can't just press the d-pad up or down and tap the action button to make Sonic shoot off like a missile. Whenever you start to perform the Spin Dash Attack or the Super Peel Out, the screen starts to move in the direction Sonic will be going in and if you let up on the button before the screen stops moving, Sonic stops revving up.
I've probably been nastier on Sonic CD here than I really meant to be. I've been a Sonic fan since the first game, and I genuinely like Sonic CD. It's just that when you have such a high expectation to live up to, you're bound to be let down. Sonic CD has a reputation which is simply too high to live up to, and when that happens, the flaws tend to be a lot more apparent. Sonic CD is a great game. But it isn't the revelatory experience its boosters play it up to be. If you Sonic CD it in a store, by all means buy it. But it isn't worth endlessly scouring and fighting bidding wars on Ebay for.