He confirmed that his demos were basically the only thing that were really developed on final hardware, and utilized it's performance at least partially, and also said that Ducky demo was more complex and better looking than the one he did for the PS2. PSP version uses spherical harmonics lighting for realistic global scene illumination, and so does the cityscape demo which calculates global lighting and global soft shadows in realtime. He even said that with some more time he could optimize those routines to run 3-4x faster than they currently do (and yet they still run at 60FPS with given scenes)
Btw, the guy in question programmed Starfox, Starfox 2 and helped develop the 3D coprocessor chip for SNES, worked for SCAE and SCEJ, now he's a founder of Q-games.