Drawing from the hard sci-fi of the late 70s and early 80s, Star Command is an RPG/military strategy/hand-to-hand/ship-to-ship combat game that really hasn't been bested in anything other than graphics. And, yes, the graphics for this game are poor, almost negligible, but if you're here for the pretty, then you're missing the point.
You create a squad of soldiers from the ground up, training their attributes and skills, then buying and equipping them with weapons and equipment. This stuff will be really low-quality at first, and you'll be lucky if you can find enough credits to keep all your weapons loaded, but that ends soon enough.
By the end of the game, you'll be throwing out white-hot plasma and tossing antimatter grenades like they're Skittles.
You have the option of making one of your crew an Esper, a character with psycho powers that can disable and even kill your opponents. The class isn't as fully rounded out as it could be, but it does a good job.
Hand-to-hand combat is done in a style similar to the old Ultima games, with a chessboard-like battle grid that your characters can move around on and fill with weapons fire as they see fit.
Oh, and you have a ship. Equip it with shield and weapons, upgrade it to a newer model and gun against the ships that fill the galaxy. As an added bonus, if you
can overlap your ship with the enemy, you're back to hand-to-hand combat. Fun!
The game runs you through a series of missions, each of which nets you some cash and a chance for promotion. These are standard fetch missions and kill missions for the most part. You're looking to loot a particular element from a particular planet, or you're tracking down a particular ship in a sector, or invading an enemy base. The higher ranking your crew, the more you make. I've never been sure how you earn promotion, but I've managed as high as Commander.
Beyond that, the game is open-ended in a way that many modern strategy games can only hope for. You can look for sellable elements on just about every planet you come across, fight and salvage a variety of enemy ships and generally muck about as much as you want between missions, which generally don't have any sort of time limit.
This game really is one of the truly classic games and unfortunately overlooked.