Units play walk sounds when they move. If unit is on screen, sound is played for every visible "step" of the sprite (or something like that for non-walking aliens). If unit is not on screen however, the sound is not always played. However, a different sound - "cry" - is played for aliens that are not on screen. We need to figure all this out to make it vanilla-like in OpenApoc. Questions: - How is walk sound volume determined? Is it based on distance to screen center? Is it the same for non-visible units? Or is it based on distance to closest operative? - Is walk sound played for every step when unit is not visible? What about TB? Game seems to speed up calculations in TB, and there's no "clustering" of sounds of walking - does game skip playing walk sounds if more than one unit walks at the same time? Or does it somehow throttle walk sounds of non-visible units? Maybe it just throttles walk sounds all the time, like, "no more than 4 sounds at once"? (can be tested by making 18 units walk on screen at same time) - How frequently is cry sound played? Is frequency dependent on amount of aliens (more cries per turn if more aliens? or same?) - Every alien type has same chance to cry or is it based on population? Ex: if 10 anthropods and 2 spitters are on map, are we 5 times more likely to hear anthropods?