Quartz Quadrant is the fourth Round of Sonic the Hedgehog CD. Like with every other Round in the game, Quartz Quadrant consists of two standard Zones that span all time zones, followed by a shorter third Zone set in the future which contains the boss. Geographically, Quartz Quadrant is located on the Little Planet.
Set in a semi-underground mine, Quartz Quadrant features both internal and external backgrounds. Indoors, the player is almost completely surrounded by quartz and other minerals that are in the process of being mined by all the machinery for an unknown purpose. Outdoors, the player is treated to an abstract forest with brown rock formations and waterfalls.
A common setpiece throughout the Round are rooms that separate both backgrounds, which are very spacious and have red Springs to bounce the player around as well as the robot transporter. Since this Round is a bit more cramped everywhere else than most other Rounds, it will be harder for the player to get to the Past. The bottom of the stage is mostly flat, though. This makes getting to the end and/or Past easier.
The central gimmick in this level is being able to control the direction of the many conveyor belts on the ground and on floating platforms. The player can do this by running past a sign with an arrow on it. Each time they run past it, it will change which way the conveyor belts will go. This will also affect the direction the vertical spin tunnels will carry the player, which the player can use for an easy time warp in most versions of the game. However, this is made harder in the 2011 re-release as simply walking into them will not activate the time warp; the player has to build up speed, then jump in without losing momentum.
Other hazards the player must watch out for are blocks that will fall down when the player passes underneath them and break upon hitting the ground. In the Past, these are stalactites instead. Another mechanic found throughout the Round are glass tubes that wind around in a coil in one part of the foreground. Though these can get a time warp going, they don't last long enough to maintain it, so the player must keep on moving afterwards.
|The interior of a crystal mining site. Run through by making full use of the conveyer belt to change the direction of travel. Watch out for falling boulders, push on through the fast spiral tube!
— Sonic the Hedgehog CD JP manual (translation by Vertekins)
|Look out for falling rocks as you race through a treasure trove of glittering gems. Touch the arrow signs to change the direction of the moving conveyor belts. Spiny snails, slimy caterpillars and cannon-toting beetles will try their best to slow you down!
— Sonic the Hedgehog CD US manual
Differences between Time Zones
|The Present is a large mining facility, with contraptions built in, such as conveyor belts. There is still a large amount of quartz to be mined, and some is just lying around.
|The mine of the Past uses more simple machines, and almost everything is made from wood. The caves are filled with a lime green ooze with crystals poking out of it, and the exterior holds a giant lake with driftwood. Badniks are more scarce in the Past, but that doesn't mean that it won't cause...
|...the future to become a wasteland of smoke-filled skies! All of the quartz in the caves has been completely mined out, and most of the outdoors has become Dr. Eggman's dystopian cities, and he still has his Badniks in the same position as before.
|If you manage to stop Eggman's production of robots, the future will turn brighter. The mining has stopped, and the exposed crystals shimmer in the background of the caves. The outdoors will even sport futuristic domes and shrubbery replacing the waterfalls.