The game requires the player to navigate labyrinthine mines while fighting virus-infected robots. The player is given the clear objective to find and destroy each mine’s reactor core and escape before the mine is destroyed by the meltdown. Occasionally, for some levels, the reactor core is replaced with a boss, changing the objective that the player must destroy the boss in order to trigger the meltdown and escape before the mine blows up. To obtain access to the reactor, the player must collect the blue, yellow, and/or red access keys for each level, which are required to open doors. As an optional objective, the player can also choose to rescue PTMC workers who were taken hostage by the infected robots. Descent features a complementary points system. Players can score points by destroying enemy robots, picking up power-ups, and detonating the reactor. Bonus points are awarded upon completion of each level. These bonus points are based upon the player’s shield and energy count, the skill level played, and a combination of picking up any hostages and safely rescuing them. Descent demands that players keep their sense of orientation in a fully 3D environment with a flight model featuring six degrees of freedom in zero-gravity. Traditional FPS gamesrequire the player to only control two axes and their heading. By employing six degrees of movement, the player is given additional control for vertical movement and banking, introducing more movement controls than traditional FPS games. Descent ’s unique movement controls also increase the possibility for players to experience motion sickness or nausea – a common complaint found in reviews for the game.