Well I think only that particular piece of software will know how to understand the data, as it is complex and made of many packets stuck together. You will need to learn about that particular program I think.
Well yeah I can see that. What are you using to analyse the packets? Is it Ethereal? All the packets you can see are stuck back together at the other end by the software. So you will need to know where a "block" of data begins and ends I think, before you can start analysing the data.
You look at packets, the plain text, from IM programs for example, can be read by humans because it is text, human readable, nice and easy. But for things like games, there are co-ordinates for players and other numbers and much more involved, so you need to know how the software works.