Prisoner of Echo provides players with an exciting journey navigating mines and using sound waves to unlock doors and hide from enemies. The story is compelling and the gameplay is interesting, but I feel like more could have been done to educate the player on principles of sound waves. The player picks a sound sample, frequency, and amplitude to match the requirements of the door they are trying to open, but the game depends on players to study the changing wave shape as they adjust values to deduce the actual principles at work.