In Deep Black the player takes the role of an expert force specialised in undersea combat. The protagonist is up against terrorists which have their headquarters inside the ocean - which means he has to infiltrate those bases.
This game is a third-person shooter with levels located partly under water and inside said bases. On land the game is a traditional cover-based shooter: the player uses 14 weapons with primary and secondary fire modes to shoot at the approaching enemies. By pressing a button he takes cover and shoots from there. Under water he dives, but the main change is that the enemies are mechanical drones which also can be destroyed in melee combat by mastering a quick time event.
The soldier also has a jet pack, grenades and a grappling hook in his backpack which is used to solve simple puzzles, stealthily kill guards by pulling them into the water or reprogram drones so they become friendly. The levels are strictly linear.