Apeiron is a Mac OS Classic clone of Centipede by Ambrosia Software. As is typical of Ambrosia Software's Mac OS games, it's over-the-top and psychedelic, far moreso than a Centipede clone should be.
Picture ID #152 in the Apeiron application is the Greek letters Phi Delta Theta, which was author Andrew Welch's fraternity at the Rochester Institute of Technology.
Picture ID #666, Harley.cust.pictRes, is a photo of Welch riding a Harley.
The Apeiron application contains a sound file (ID #666) labeled "yelaH nhoJ", after Ambrosia's marketing manager John Haley.
When reversed, the sound is a voice (probably Haley's) saying "Ooh, I'm touching myself!" in an exaggerated accent.