Energy is also used to repair units and structures. This is important, because as units earn kills their effectiveness increases. It's also far cheaper to repair damaged units in terms of energy, not to mention the precious metal, than to create new ones. Units and Combat There are a wide variety of land, sea and air units in the game. Each combatant has unique units, although they have similar functions.
Units come in three levels.
Higher level units are more expensive and can only be built by special facilities. They are, however, much more powerful in combat and there are also specialty units like mobile radar jammers and mobile radar units to play with. You'll also find submarines, mobile mines and a host of other nifty gizmos to play with. And that's one of the ways in which Total Annihilation really stands out. With great differences in speed, range, and killing power the units really are varied.