In an interview, the staff explained Pictochat, the built in messaging program on the Nintendo DS, and the idea of trailing light tracks inspired its development. The next question addressed voice acting and the team explained Knights in the Nightmare only has English voice acting. The developers felt expressing a dark fantasy world in Japanese would be difficult.
Just before the DS version came out, the team thought “why not the PSP?” Knights in the Nightmare was designed with stylus controls on the Nintendo DS. Since the PSP doesn’t have a touch screen Sting fixed the game to work with an analog stick. While reworking the game, Sting changed the shape and patterns for some of the bullets. Due to hardware differences, the background music was reworked too.
The PSP version of Knights in the Nightmare is slated for April 22 in Japan. Atlus, who is also handling the Japanese version, has not announced a US release.