That could be possible but not likely, generally in a game you would send thousands of packets a minute if not more! All you were getting were constant SYNs, I highly doubt that because you only got a couple packets from every person instead of thousands but it could be a DoS or that new SQL worm hitting you, not only your gamers try to access your server, your probably get around 3 hits a day from NIMDA and god knows how many from the SQL worm as well as kiddie scans, but that's just impossible.
EDIT: A ratio of around 3 packets to 100,000 packets != the ratio of 5 to 3-5
