In Countdown to Shutdown you control eight droids on the mission to find the core room of an nuclear power plant, in which a serious explosion has caused large casualties.
The game is an arcade-like 3D adventure, you see always only the room your droid moves in, in the bottom of the screen you receive information like actual core temp and radiation level, time remaining, the direction you heading for, information about your shield level and others . Once you found the core room you must attempt to damp down the reactor temperature to avoid a major catastrophe a second explosion will cause.
With the joystick you control all 8 droids, you have to switch several times between them because of the fact, that each of them has a special ability (like scientific, medical, technical, combat, intelligence, power, strength and mobility). Over 2.000 rooms on 8 levels waiting for you. Examine all rooms (press "E" on your keyboard) for useful and often required items and valuables (like weapons, medical or technical tool sets) - each of your droids is able to keep 8 items in his inventory. Beware of radiation (the closer you get to the core room, the more it increases, before entering the core room you need to find and activate radiation shields), defense droids which were installed to keep out intruders (like you!) and Plasma. Because of the first explosion some doors between rooms were blocked or damaged: Find the needed technical tool sets for example to fix such issues.
Once you have found the core room, use the abilities of your different droids and the - hopefully found - correct tools to damp down the temperature and stop the disaster.