This stage is exclusive to the arcade version of Gradius III. It takes place in a pseudo-3D environment seen from a third person perspective behind the player's ship. The player has to make their way through tight, dwindling tunnels at a very high speed. There are no enemies to be encountered in this level, with the real challenge being on trying not to collide with the caverns' walls.
The entire course is scattered with Power Capsules, which makes this level act more like a bonus round than a real stage. Once the player out, the stage returns back to side-scrolling again and head to Moai Zone.
|Theme of High Speed Dimension.|
|Stages||Desert • Bubble Zone • Volcanic Planet • High Speed Dimension • Moai Zone • Cell Planet • Prominence Planet • Plant Planet • Crystal Zone • Boss Rush • Mechanical Base|
|SNES exclusive stages||High Speed Zone • Fortress • Cell|
|Bosses||Goliath • Bubble Eye • Godrei • Big Core MK III • Dogas • Vaif • Twin Vaif (SNES) • Gregol • Wyvern • Vulture Dragon • Choking Weed • Lizard Core • Beacon (SNES) • Tetran • Covered Core • Big Core MK II • Crystal Core • Death MK II • Dellinger Core • Disrupt • Shadow Gear • Shadow Gear MK II (SNES) • Big Core • Golem • Bacterian|