But back to business. Running from the start to the finish isn't the only activity you'll find within these elaborate stages. Remember that whole time travel thing? Scattered around each Zone like traditional Lampposts are Time Warp signs reading "PAST" or "FUTURE." I guess that's pretty self-explanitory. Once you've flipped a sign, attain max speed and hold it for three seconds in order to warp to the time zone indicated on the sign. (For example: if you're in the present and flip a PAST sign, you'll go to the past. If you're in the future and flip a PAST sign, you'll go to the present.) Careful with that, though...if you get stopped or take a hit while the sign is flashing, you'll blow the warp and remain in the time you're in. (And once a sign has been flipped, it can't be flipped again.) Here's the correct way to play any given Zone, if you want to see the whole shebang and achieve the good ending: first, warp to the past and locate the robot machine. Bust that booger, and all the Badniks in the past will go vamoose. (You may also want to search out and destroy the Metal Sonic hologram for points. Once that's out of the way, those cute furries will prance happily around the level.) That alone will score you a Good Future, but what's the point of that if you don't get to see your handiwork? Flash back to the present, where everything will be just as you left it. Now pop into the future to witness the Good Future, a beautiful and Badnik-free scenario where technology and nature share equal parts of the scenery. If you take a trip to the future before destroying the robot machine in the past, you'll be in the bad future: a polluted, mechanical mess akin to all those factory Zones Robotnik hangs out in. The third Zone (known as "Acts" in other Sonic games) in any Round (known as "Zones" in other Sonic games) is the boss battle, and automatically takes place in the future. If you attained a Good Future in both previous Zones, then the boss round will also be in the lovely land. Otherwise, it's grimesville.

   Speaking of bosses, you'll find they take on quite a different light. They only withstand three spins a piece, but just landing a hit on those nasty machines is an accomplishment in itself. Robotnik's gadgets have some extra good defense systems this time around...

   Just like Sonic 1, you can enter a Special Stage by leaping into the giant Rings that appear at the end of a Zone (provided you've got 50 Rings on-hand). Designed specifically to take advantage of the Sega CD's scrolling capabilities, the Special Stages find Sonic running through paper-flat 3D fields, with squares on the ground having varying functions. The object is to chase down and destroy the six UFOs within the time limit, after which you're rewarded with a Time Stone. Your biggest enemy is the water that weaves in and around each stage...take a dip and you get a whopping 10 seconds shaved off the timer. Ouch. Items you'll find along the ground include:

• Chopper Blocks -- Send Sonic falling flat on his face, and you lose your Rings to boot
• Fan Blocks -- Send Sonic whirling through the air
• Spring Blocks -- Send Sonic zooming straight upward
• Dash Zones -- Give Sonic a burst of speed in the direction the arrow points
• Bumpers -- Sonic bounces right off these puppies

   Seven levels of high-speed goodness this time around:

• Palmtree Panic -- It's like the other tropical levels except...pointier. Home to Anton, Patabata, and Masukii.
• Collision Chaos -- The next member of the pinball family. It's very...pink. This Zone can't be described man, just play it. Home to Kamakama and Batapyon.
• Tidal Tempest -- Under the sea, under the seeeaaa...er, well, in the underwater caverns beneath an active volcano range, anyway.
• Quartz Quadrant -- You're in these old mining caves lined with, you guessed it, quartz (and some other various crystal formations). Home to Kumokumo, Noronoro, and Saasorii.
• Wacky Workbench -- It's a giant factory, but there's an interesting gimmick going on: the entire floor is like a giant spring. Step on it when it's flashing, and you'll go bouncing into the air. Look for a strange goddess statue hidden in the past: it causes Rings to sprinkle from the ceiling! You'll find a Robotnik statue in the future: destroy it or it causes mines to fall upon you. Home to Mekabi.
• Stardust Speedway -- It's a highway in the nighttime sky above a fantastic city. There's a giant spire in the center in the past, which is replaced by a giant Eggman structure in the present and bad future. Home to Pobii.
• Metallic Madness -- It is, not surprisingly, a giant industrial city of metal. Home to Tagataga.

   The classic assortment of items is here, also:

• Power Sneakers -- Temporarily raises your speed
• Super Ring -- Worth 10 Rings
• 1-Up -- Gives you an extra chance
• Invincible -- Makes you invincible for a short time
• Shield -- Protects you from one hit

   One other thing Sonic CD touts that others in the series can't are numerous gameplay modes. You can start a New Game, after which you'll be able to select the Continue option, which saves your previous game. Unfortunately, it only holds one game at a time, and it's erased as soon as you start a new one. The Time Attack mode lets you race the clock in Zones and Special Stages you've already completed, after which you get to enter your initials. (Get the most sets of initials on the board, and you get a special screen after completing the regular game. It features Sonic, Amy, and Metal Sonic running around the screen, while numerous animals frolick happily; along with the text: "Congratulations [your initials here]! You are greatest player!" Mm, how sweet it is!) There are also a couple of hidden modes that are unlocked after you've topped enough of your old Time Attack scores: D.A. Garden and Visual Mode. D.A. Garden is an elaborate sound test, while Visual Mode allows you to view the game's anime intro and both endings, along with a special "pencil test" of the incomplete movies.