Primitive Units. QuadVees. Superheavy 'Mechs. Weapons of Mass Destruction. Robotic and Drone Systems. Land-Air BattleMechs.
As you delve into BattleTech lore, additional weapons, units, and rules become available to you and your foces as you fight in the Dark Age, Jihad, or even the depths of the Star League Eras, and all the way back into the Age of War before the birth of the BattleMech.
Alternate Eras introduces a huge swath of rules for playing across thousands of years of BattleTech history, including weapons and equipment mostly unique to a given era.