Siliconera reports that earlier builds of the PSP version of Echochrome were contrast reversed with a black background and blocks drawn with white lines. The final version is on the horizon in Japan, and the most recent trailer shows a PSP playing Echochrome with a white background (see the video clip below.) The reversal of background/line color was a small but notable change.
The clip goes through the five subjective laws that govern the world of Echochrome. In canvas mode, players can create their own Echochrome levels and share them through an ad hoc connection. Siliconera is curious to see how the PSP version compares to the PS3 version that will come out on the same day.