Mission Critical is a sci-fi adventure game, created by Legend Entertainment for MS-DOS, written by the company's CEO Mike Verdu, and released in November 1995.

The games storyline focuses on the player taking on the role of a single crew member, who is left behind on their ship after their captain feigns a surrender to ensure a vital mission can continue.

The player's goal focuses on repairing their ship after a recent battle, and then getting to the surface of a planet to complete a secret scientific mission that could provide the means to ending a war over technological advancements and artificial life.

A few locations use a mixture of computer generated images and highly detailed, hand-painted backdrops, with some 2D animation effects to compensate for the lack of transition movies in these parts.

In the 22nd century, the United Nations (UN) has evolved from a diplomatic organization to a political group that form the laws and rules for humanity, rather than the planet's many sovereign states.

In response, several nations, including the United States, and various colonies beyond Earth secede from the UN and form a military political coalition called "The Alliance", with a belief that technological development, and the possible deaths it can cause, far outweighs the restrictions on freedom imposed on humanity.

The resulting split leads to a conflict between the UN, having greater production capabilities, and the Alliance, who holds its own with advanced technologies, which has lasted for two decades and devolved into a war of attrition.

The cast includes Michael Dorn as Captain Stephen R. Dayna, Patricia Charbonneau as Executive officer Jennifer Tran, and Henry Strozier as Alliance Fleet Admiral Charles Decker.

After the pair chose one member (the player), Tran leave messages for them to receive when they recover consciousness, before leading a warhead onto the ship's inter-ship shuttle.

Revealing that the UN are sending more ships to the star system, and advises the player to order the Lexington's main computer to move the two vessels to safety.

The player, despite this knowledge, refuses to give up, and learns from Decker that the UN ships could be defeated through the use of an experimental chemical enhancer aboard the Lexington called "HYPE", which allows the user to be able to micromanage combat drones in space combat more efficiently than normal humans can due to the speed of space battles; however, the user will suffer serious side effects in time that eventually lead to death.

With this knowledge, the player proceeds with their mission by bringing the lander from the Jericho to the Lexington, preparing it for the descent to the surface, and then using a syrum of HYPE in order to defend the vessels from the UN.

Inside, he uncovers technology that allows him to form machinery reconstructed from metal scattered around the ruins and surface, which in turn build a time gate.

The player learns that in order to win their war, the UN used a weapon of mass destruction to destroy the Tal-Seto network, while sending the surviving humans out of the galaxy on a ship with new engine drives.

Using a special program, the ELFs reveal how they intend to send the player's consciousness back into the past before the attack by the Dharma, in the hopes they can change history and prevent the unfolding disaster in this timeline.

[9] In 2000, a Computer Games Strategy Plus retrospective said of Mission Critical, "A terrific storyline, excellent puzzles and a superb tactical combat engine (!)