Part flight-sim, part interactive movie I would say these games were perhaps the most successful results of the Full Motion Video dalliance of the late 90s.
Mark "Luke Skywalker" Hamill stars as Blair (the hero in Wing Commander 1-4). You might argue that going from being the ace Jedi pilot of the rebellion flying against the Empire to being the ace aging pilot of the Confederation flying against the Kilrathi Empire was not much of a stretch for Mark but the characters were quite different. Tom "That guy who was Biff" Wilson plays the annoying butt-head of a sidekick, Maniac, your oft wingman who never follows orders and only survives by sheer chance. By the way if you haven't seen his Back to the Future song see it here!
Malcolm "Clockwork Orange" MacDowell as Admiral Tolwyn and John "Indy" Rhys-Davies as Paladin also added to the respectable caliber of actors to appear in the games - a particularly good cast for a computer game.
The plot of the first three games was the good Confederation were under attack by the evil Kilrathi Empire, a race of evolved warlike cats. In WC1 and 2 the Confederation were the clear goodies, and beyond what happened in your missions there was no way to influence the plotlines. WC1 had a relatively straightforward plotline, while WC2 was literally crying out to be made into a film:-
As the games moved into Full Motion Video WC3 and WC4 were definitely more shades of greys - feeling like a cross between Top Gun, Babylon 5 and Star Wars. As far back as WC2 your wingmen would die in battle, or as the results of nefarious plots. It was dark stuff - WC3 ends with you blowing up the Kilrathi home world:-
Essentially the game comprised of full-motion segments which would occasionally pause and allow you the player to make a decision as to how Mark Hamill's character reacts to the situation. This would then impact subsequent missions. Also by WC3 Hamill's character, Blair, was a Colonel and thus made command level decisions regarding missions. The actual flight-sim itself contained video segments to handle inter-ship communications but for the most part you just shot things and completed your mission objectives. If you failed enough missions bad stuff happened in the overall storyline, usually leading to you being removed of command, Earth being nuked by the Kilrathi, being shot as a traitor or any other number of bad things. There were so many possible permeatations in the storyline - WC3 even had a choice of 2 love interests affecting the end of the game.
Wing Commander 4 was my favourite of the games however - it is set after the Kilrathi wars (bit difficult to continue a war when your homeland has been nuked). The following clip does a good job of explaining matters:-
It was epic, lavishly filmed. Wing Commander 3 was rather obviously filmed on a blue screen, but for Wing Commander 4 they went to town and spent millions on essentially filming a proper sci-fi movie. Nowhere is this more evident than in the intro:-
Despite being a space-sim the end of WC4 is largely dependant on your choices in the cinematic sequences:-
There was a Wing Commander 5 featuring a new main character and (true to Tolwyn's predictions) a new alien threat, but to be honest it was nowhere near as good as WDC4. Wing Commander: Prophecy was a passing of the torch game, where Hamill's Blair turned up to give the new hero the thumbs up. Despite being the greatest pilot in the galaxy on the two missions he features in as a pilot, he is captured and (presumably) killed:-
Note to self: When on big alien mothership run, not walk, back to your mode of transport.
There was supposed to be a Wing Commander 6 and 7 to tie up the alien threat, but the market fell out of the full motion video market and the line was dropped by Origin Systems.
Wing Commander was ripe to spin off on to TV and cinema. Wing Commander Academy was surprisingly gritty for a Saturday morning cartoon series, featuring the voices of Hamill, Wilson and Macdowell as younger versions of the game characters. It lasted 13 episodes but way very true to the spirit of the games.
There was also a Wing Commander movie, starting Freddie "I took Buffy off the market" Prinze Jnr. as Blair and Matthew "That Bloke From Scream" Lilliard as Maniac. Personally I thought it was a good film despite Prinze's presence, the new quasi-religious Jedi mumbo-jumbo (Blair is the last of the pilgrims, a genetically superior race of spacefaring humans) and the continual WW2 motifs (and the fact that ships launching off the carriers appear to be under the influence of gravity in deep space).