Deep Rock Galactic is a first-person cooperative wave shooter, built with randomly generated terrain, supplemented by stellar design of enemies, weapons, and characters. The main features of the game are its previously mentioned random-gen terrain for levels, and its class-based coop horde shooting.
To give a quick rundown, you get to choose from four different classes, Driller, Engineer, Gunner and Scout. Each class has a unique primary and secondary weapon, as well as grenades, a support and mobility tool. This means that each class has four different tools, and then grenades as options for combat and exploration. With the many available unlocks and upgrades available the loadout system allows for even further diversifying of classes.
On top of the weapon progression available, cosmetic options are plentiful with the only DLC the game has to offer being purely cosmetic, which is also not to say any DLC is needed. From my playing of the game personally I have not yet bought a single DLC for the game and have dozens of options for each class.
Overall, I cannot recommend this game enough to anyone who loves coop games, especially in the vein of Left 4 Dead, Vermintide, or Killing Floor. Deep Rock Galactic very strongly adds its name to the list of amazing games to play with friends and with a price of $30 on Steam, often going on sale, it is well worth the price.