Thank you, Gilberto!
Let me show you why I think that the sound designer of the game may have not applied a slow attack.
If you apply a slow attack, precisely a 1ms exponential attack, such as the following:
...to various tones, you get waveforms like the following ones (all within a single cycle time window):
The higher the tone, the easier it becomes to see and measure distortion (within those 1ms periods). (Here I'm using the term distortion meaning deviation from a sine tone, and not that it is a bad sounding thing!).
In the sounds of the game, there's nothing like any of the above waveforms. As I wrote, the sounds of the game have a frozen phase, W always starts start in the positive domain. I've only found clean repetitive sine tones. The sound designer just wanted to make a simple game, not dsp fireworks!
I hope these last pics help you to see what I've seen.
By the way, when I say "Ping-pong delay is the answer", there's no arrogance in it. That's just a rough conclusion, a quick one, for the sake of clarity and simplicity! There can be many answers, maybe the more answers the better. Ping-pong delay is just one of many possible answers.
I live and love in Argentina