Dark Valley is a racecourse in Sonic Drift 2 for the Sega Game Gear. This stage (as "Dark Valley 1") is the third track of the Purple Chaos GP, after Hill Top 1 and before Casino Night; and the races re-enter the region during the Blue Chaos GP, where "Dark Valley 2" is the first track, before Quake Cave.
The stage takes place amongst the ridges and crags of a deserted mountain range; an area which seems wreathed in permanent shadow cast by the towering rocky peaks. Dark Valley features a racetrack with yawning voids on either side of the roadway; veer off course and it's a long way down.
Dark Valley also features occasional gaps in the track where the entire surface is gone - replaced by a pitch-black abyss. Make sure you hit the springs that come up before these absences, or once again you'll be taking the fastest way to the jagged rocks on the bottom.