God damn these guys are n00bs.
Here, I'll tell you how these script kiddies hack games. It's preventable, just some are too stupid to stop it.
Alright first thing is first,
You have to get a Flash Decompiler, like Sothink SWF Decompiler, I highly recommend it. You open up the SWF, and you can either save it as a .fla, or search inside the program for the "http://" tag, I'm pretty sure you use openURL() to insert a score, I forgot. So try finding something that relates to a scoreboard, such as scoreboard.php?insert=$variable&name=$name, if you can't find any results, search for ".php?" and take the URL, find the scoreboard if the URL is incomplete, and paste the code after it, subsituting your score for their variables, and viola, it's done.
There are also other ways, like Ethereal, where you can just run it, and capture the packets, and search them for the URL script.
Congrats, now you can go PWN some Flash Game. XD
Here is an example URL:
Of course, some may encrypt the code, but it's easily decrypted because it has to be translated in flash, which is basically open source.