Many of Digital Pictures' Sega CD titles had a "bonus" redbook audio track. If you put the CD into a standard audio CD player and selected Track 2, you would get the following recording:
"Good Afternoon, Digital Pictures"
(zombie-like chanting of "enin rebmun" repeated three times)
Reversing the chanting reveals it to be the words "number nine" reversed - presumably a reference to the Beatles' experimental song "Revolution 9" on the White Album. It likely has further meaning to former employees as a Digital Pictures "in-joke."