Make clientside playback more robust

The smallest discrepancy in debug recording playback can cause clientside playback to fail; chief mechanism is that the client sends something slightly different to the server on playback, expects a different response, but only gets the original response it no longer recognizes.

Most affected would be ack packets.

Many playback failures could be avoided if, by default, the client would simply not expect any acknowledgements from the server. It should be activatable to be able to debug issues with that system, but normally, debug focus is on something else.