blue, yellow, or red and require a key of the corresponding color to be opened. In addition to brightening passages by shooting flares or turning on a headlight if the latter has been picked up, at least three measures can be used to prevent getting lost in the mines, two of which are using a wireframe automap that documents all explored areas of the mine and dropping markers in certain locations. The markers are displayed on the automap. Along the way, the player may also find and free a Guide-Bot, a commandable scouting assistant that guides the player to a specified objective or powerup. Additionally, many stages have human hostages that award an additional point bonus if they are rescued before completing the level. Within each level, the player may find and collect power-ups scattered throughout the mine or dropped by dying robots. Many of the power-ups expand the ship's weaponry, which is divided into primary and secondary weapons. Primary weapons range from a variety of pulse lasers and plasma bolts, and all of them consume energy in varying increments, except for two rotary cannons whose ammunition consists of explosive shells instead. Secondary weapons include many types of missiles, and mines which are dropped behind the player's ship to slow pursuing enemies. Ten new weapons have been added for Descent II of which some are upgrades from the original Descent weapons which are all present as well; new weapons include the Phoenix cannon which fires energy orbs that rebound off walls, the Omega cannon which fires electrostatic discharge, and the Guided Missile which can be remote piloted by the player. The player can also collect equipment items which grant special abilities. For example, a converter exists for converting energy in excess of 100 units into shields, whereas the afterburner allows the player to temporarily fly forward twice as fast. Levels may contain energy stations the player can fly through to recharge their ship's energy level while in motion, as well as generators that spawn more robots. Shooting out certain control panels causes a variety of events, such as doors opening, walls being removed, or force fields being deactivated. In a few levels, behind some hidden doors are teleporters that warp the player to the current star system's secret level. These secret levels are not required to complete the game but contain many power-ups, and can be revisited provided that their