The game play follows typical controls, though you could also play with a joy stick if you so desired. It is a First Person Shooter, so the perspective is the same as DOOM in that it has you looking out through the eyes of Kattarn. You are able to pick up shields and power ups throughout the game, just as you are with other FPSs, and are able to jump, duck, and look up and down—following the conventions that DOOM put in place with its release. Star Wars: Dark Forces also includes some larger Zelda-esque puzzles, like huge mazes that are controlled by numerous switches—something that I think is usually foreign from the FPS genre.
Each level of the game is essentially a "mission" with an objective and goals attached to it, and there are fourteen in total. This is not, however, a free world and you are required to follow a linear plot that is moved forward by sometimes long-winded cut sequences, such as the one that makes up much of the video below. Many of the levels surround the idea of the deterring the building of new Troopers and Droids as well as the collection of materials required to do so. This can be anything from rescuing captured allies to fighting a dragon with your bare hands. Ultimately, Kattarn is just a total bad ass that no one can really keep down—thought most of the fights do tend to err on the ranged side of things.
If you enjoyed any of the other Star Wars games that can after this ones release, I would solid recommend trying to get your hands on this one and play it if you hadn't already. It is foundational for the series as the whole, and also spawned a great deal of fanfiction and novel content about the Star Wars universe. While not much different from your average FPS this differentiates itself by having slightly different conventions, and being set in a universe we are all already familiar with and invested in. If you would like to try to play it online, you can do so here. Happy gaming!