Meltdown is the name of two different games released using the 3D Game Creation System.
The first Meltdown is a short official demonstration for the GCS made in March 1995 by Terry F. Hamel, an additional level designer for Blood by Monolith Productions and a Doom custom mapper. The player had to escape from a military compound by bypassing an energy barrier to pick up an elevator key. It is also known simply as GCS Demo.
A separate game by this title was also created by Robert Cureton using the GCS.