The Kilrathi Admiral killed in front of the Emperor at the winning ending was supposed to be Emperor's son, i.e. the crown prince, and father of Prince Thrakkath, the villain in WC2 and WC3.
In the first printing of Wing Commander, there was a coupon included to get the Secret Missions disk at discount for $20. Origin, figuring demand would be low, had only printed up a few hundred copies. They were then horrified when they were almost immediately flooded with thousands of requests, creating a rather lengthy backlog. (of which I was part) All retail copies of the SMs then sold for $30.