Dragon Rock, Star Fox Adventures' final SpellStone area, was considerably larger and more complex in earlier versions of the game than in the final release. Both the leaked December 2000 build of Dinosaur Planet and also the E3 2002 kiosk version of Star Fox Adventures show that Dragon Rock featured a slew of additional areas that didn't make the final cut, such as an underground quarry area where Sabre/Fox would have to save the imprisoned EarthWalker from being eaten by a group of creatures known as Skeetlas, and also a large underground mining facility Sabre/Fox could only access by flying the imprisoned CloudRunner to the top of the titular Dragon Rock (a giant tower in SFA) at the center of the map. In SFA's case, Fox would have to solve a puzzle that would involve powering the portal at the back end of the room that would grant him access to Drakor, Dragon Rock's boss.

In the final release, both the underground quarry and the mining facility were removed: Fox simply frees the EarthWalker from a corral on the surface by hitting a switch located nearby the imprisoned HighTop from across the map, and Fox immediately skips to fighting Drakor after being dropped off by the CloudRunner at the top of the center tower. Funny enough, when Fox lands on the platform in Drakor's arena, it bizarrely shows electricity spewing around him, which was a remnant of the portal he was supposed to activate in the cut mining facility segment in order to access the boss.

The SFA dev team admitted on a 2003 Rare Scribes that Dragon Rock was massively scaled back from its intended design due to "approaching deadlines", presumably referring to the impending Microsoft buyout in 2002. It's worth pointing out that the mining facility area can actually be found in the files of the final retail release of SFA and surprisingly in a much more complete state than the kiosk's version, which indicates that the dev team continued working on this area in the final months of development but ran out of time to polish it to their liking.