I think I stumbled upon something. I just played "Megatack" which is also made by Centuri. The game looks nearly identical to Challenger. I also am getting no sound with this game. So I pressed F2 to go to the Service and I went to the audio section and I ran the tests for both games and there is a list of sounds/sound effects. For each one, the test was "No"... meaning that the sound wasn't enabled/working. How do I enable it? I posted a snapshot of the "Megatack" game's service screen.