Heavy Nova is a mecha fighting game for up to two players. The single-player mode, in which the player's robot Idar must fight every CPU opponent in order, also includes interstitial platforming sequences in which the player has to reach the end fight with as much of their health intact as possible.
The game was one of two launch games for the Mega CD peripheral in Japan, which debuted on December 12th, 1991. On the same month it appeared on the Sega Genesis in North America with the CD-based features missing (like redbook audio), as the Sega CD had yet to launch in that region.
In the future, Earth has been all but exhausted of her resources and the environment is in shambles. Suddenly, a benevolent race of advanced aliens from the planet Akirov step in. They claim to have been observing humanity and have intervened, repaired the environment, and taught mankind to travel further into space.
Sadly the Akirovians were only preparing to take over the Earth. The humans fought back and eventually drove them back out of the Solar System. Mankind's victory was due largely to re-appropriated technology: Heavy D.O.L.L.s (Defensive Offensive Lethal Liberator). Giant, remote controlled, robots used not only for military purposes, but also in any task too dangerous for a human.
Now, in 2120, the most desired military rank is that of the top Heavy D.O.L.L. operator. That rank is known as "Heavy Nova", and the player character is but one soldier attempting to earn their way up to this accolade.