In Dark Forces, Kyle Katarn, a young mercenary successfully infiltrated the Empire. Jedi Knight continues the story of Katarn as he embarks on a quest into his past and learns the mysterious ways of the Jedi. With this knowledge, he must stop seven Dark Jedi from unlocking the powers of a hidden Jedi burial ground. This task forces Katarn to decide his destiny. If he chooses the Dark side, he will come into enormous power. If he chooses the Light side, he faces seemingly insurmountable evil. Whatever path Katarn chooses will change the face of the galaxy forever.
While Star Wars Dark Forces was probably one of the first SW games I played in my childhood, Dark Forces II was actually the one, which showed what Star Wars was like besides the adventures of Luke Skywalker. It presented a much larger Galaxy with its variety of weapons, enemies and new locations, which became the setting stone for the next games, released years later.
One of the most influential games in my life, no contest.
In later years, a lot of people involved in the JK community have been slagging this game whether due to its mechanics, levels, textures, plot - you name it. It's got a sympathetic (yet not really great) plot, most of the levels are fun and the FMVs are fun in their own way.
And while in many ways it also falls short of its predecessor - Dark Forces - I've never lost my ultimate faith in this game. It's good at what it's supposed to be: a Star Wars shooter (with some lightsabering).
I still like this game a lot and would recommend it to anyone interested in Star Wars while possessing no prejudice over old games.