The Rage 128 minimum requirement is a theoretical requirement. Skyrocket requires hardware 3D acceleration and will definitely not run on Macs that use software rendering, such as the Bondi iMac. Unfortunately I only have a limited amount of hardware on hand, and I sold my last Rage 128 card years ago, so I'm sorry I haven't been able to directly test it on the card.

As for the sound:
1. The "delay" in the sound is there because it is realistic. The speed of sound is much, much, much slower than the speed of light. If you go to a real fireworks show, you're always going to hear the fireworks some time after you see them because they exploded a far distance away from your vantage point.
2. You can turn the sound off by setting the volume to 0, which is the default setting.