The assualt of an enemy in his own territory is only attempted when the attacker has superior forces. Even then defenders will be quick to mobilize and man prepared defenses. The invader must rush to secure or eliminate important objectives. Time is on the side of the defender for if the initial momentum of the invasion can be halted the entire operation may falter. The scope of the conflict will be quite different then two forces battling over neutral terrain. Here the terrain almost becomes the object of the conflict with both side judging success or defeat by the positions they can hold.
 

1-10    The planet is being invaded.  Defense batteries must continue firing to
           destroy as many landing craft in the atmosphere as possible. An
           advanced force of invaders has already made planet fall and is moving
           to silence the defense batteries.

11-20  The invaders advance has so far proven unstoppable. Soon they will
           be within range to besiege the capitol. The highlands/plateau
           overlooking the capitol must be held to prevent the enemy from
           stationing artillery there.

21-30   Advanced units of the invading army have surrounded the govenors
           palace and will soon breech its defences. A commando/strike force
           must get inside to rescue him and other key officials.

31-40   Invaders have occupied and now control the plasma-reactor station
           outside the city. Defense of the city will be nearly impossible without
           the energy it provides. It must be retaken and held.

41-50   The world would have fallen long ago were it not for the abilites of
           one man. This insperational leader/brilliant tactition is all that stands
           between months of continued fighting and a quick victory. An elite
           team of assassins must make it in to his well guarded camp and
           eliminate him.

51-60   A rebel leader has been captured and is being transported to the
           capitol for interogation and trial. Rebel forces must either free or kill
           him to prevent the leaking of any secret information. The convoy
           carrying him passes through a narrow canyon/dense jungle area the
           perfect spot for an ambush.

61-70   As the main invading force advances its rear/baggage area moves
           slowly behind it. A surprise attack suddenly threatens the entire
           campaign. The small number of troops guarding the rear can't hold
           out for long against the attackers. Some of the guards are dispatched
           to break through the envelopement and get word to the main force.