Buildings

GDI Guard Tower

Once the Guard Tower/Obelisk is destroyed the enemy can just roll on in.

Nod Obelisk

GDI Infantry Barracks

Once the Infantry Barracks/Hand of Nod are destroyed only free characters are available.

Hand of Nod

GDI Refinery

Destroying the refinery early in the game ensures that the enemy can't afford many vehicles, characters or nukes.

Nod Refinery

GDI Power Plant

If the map has a Guard Tower/Obelisk the Power Plant is usually the first building to be targeted by the enemy. Once destroyed the Guard Tower/Obelisk stops working and all prices double for vehicles and characters.

NOD Power Plant

GDI Weapons Factory

Once the Weapons Factory/Airstrip is destroyed you can no longer build vehicles and you loose the harvester.

Nod Airstrip