The sound sample that comes with the gbdk is broken. This is a fixed version

Keys:

• Select: change current channel menu
• Start: play current Sound
• Start + A: play a song
• Arrows: navigate throught options
• Arrows + A: Increments/Decrements current value by 10
• Arrows + B: Increments/Decrements current value by 100
• Arrows + A + B: set Min/Max value to current option
• Select + A: Dump Registers