This list is not designed to be a complete list but it will give you something to work with besides ‘attack the hill because the enemy is on it’.
AIRFIELD: The destruction of an enemy airfield can cripple the enemy’s ability to control the air. Most modern aircraft need a runway to land and take off. All aircraft, from helicopters to Harriers, need a level area where they can be resupplied and refueled. If an aircraft is not destroyed in the attack it can be grounded. Munitions dropped from bombers or fired from artillery can crater runways making them unusable. Some munitions can be used to mine the runways in order to destroy returning aircraft. Removing the mines without damaging the runway would be a time consuming and dangerous task.
ARTILLERY or MORTARS: This is a great target because they are primarily a long range weapon that can inflict large amounts of damage. Destroying an artillery, mortar or rocket battery type unit can severely cripple a enemy’s ability to attack or defend other objectives.
ARTWORK: Attacking artwork does not have a great impact on military operations. However, it might have an impact on the enemy morale, depending on what it was and what it meant to them. Imagine someone destroying the Statue of Liberty.
BEACON: Destroying an enemy beacon can affect the enemies navigation systems. For instance, airfields use beacons quite a bit to guide in planes and helicopters, especially in inclement weather.
BRIDGE: The destruction of a bridge can force enemy units to use other routes to cross rivers or ravines. As militaries become more sophisticated and amphibious this becomes less important.
BROADCAST/RADIO FACILITY: Destroying an enemy broadcast facility can severely hamper the enemy’s ability to spread propaganda and information.
CALLIOPES/AA EMPLACEMENTS: Attacks on these targets can open the way for an air strike. Calliopes are used more for anti-missile work while AA is Anti-Aircraft. As technology improves these sites might become completely automated and deployed in ‘layers’.
COMMUNICATIONS: By attacking the enemy’s communication network you sow confusion among his ranks as commanders try to get intelligence reports, orders and coordinate movements or attacks. This may not be a physical attack, see missions TRANSMISSION (or MIJI).
COMPUTER CENTER: Attacking a computer center can have serious ramifications for the enemy. If it is a civilian network it can cause all manner of problems from power outages to telephone failures. A military computer system would maintain a lot of information that would make it worth destroying or disabling. Computer centers can also control arrays of equipment and weapons, like coastal Anti-aircraft emplacements or a missile defense system.
DAM: Destruction of a dam can affect an enemy’s power supply, or flood units down river. Destruction of a dam can also make rivers more difficult to cross.
DIPLOMATIC OBJECTIVE: This is a very broad category because it is situation dependent. Destroying a president’s vehicle can intimidate him and send the message that next time he might be in it which can affect his political outlook.
DRUG FACTORY: A problem with attacking a drug factory is that it may not be located in a country the attackers are at war with. To avoid a war with that country precautions would have to be taken. Another type of drug factory is one that provides combat troops with war drugs that increase stamina, speed, strength, pain resistance, ect.
ECM ARRAY: The Electronic countermeasures array is used to defeat or foil enemy sensors, communications and intelligence gathering. The ECM array could ‘cloak’ an enemy facility from sensors or jam enemy missiles. A wide angle HERF gun for example could be used to defend an area from cruise missiles that rely on electronics for guidance and maneuvering. (Of course the enemy probably won’t be operating electronics in that area either!).
ENGINEERS AND THEIR EQUIPMENT: Destroying trained engineers and their special equipment can seriously impact the enemy’s ability to carry out special construction projects. For example, destroying an enemy’s mobile bridges will force him to use other means to cross a river.
GROUND TO SPACE EMPLACEMENT: This can limit an enemy’s ability to attack space craft in orbit (depending on technology) or in deep space. By destroying a GtS weapon an area in orbit can be opened up so friendly space craft can support ground troops.
HABITAT: On a hostile planet this can have a serious and demoralizing effect on troops who are forced to wear protective suits. Furthermore it can have serious implications for their survival (if they need to unsuit to eat and drink).
HEADQUARTERS UNITS: These targets are also good to attack because destroying a HQ unit and killing the officers can severely demoralize the command structure. Also, when the attack is carried out by ground units the ability to recover intelligence material is superb. An attack on an HQ unit can make an attack stumble if the commander is killed because then the troops will have to reorganize or wait for orders. By killing enemy commanders it also disrupts the professionalism of a unit as new people adjust to positions and responsibilities.
HOSPITAL: Nobody who is ‘honorable’ attacks a hospital and it is against the Geneva convention, however, less scrupulous countries wouldn’t hesitate. Attacking a hospital can have a serious effect on the morale of the defenders. It would also insure that wounded soldiers do not return to duty.
INTELLIGENCE/COUNTER-INTELLIGENCE: Destroying an enemy’s intelligence/counter-intelligence resources can blind the enemy and make your own intelligence gathering easier due to lack of coordinated opposition.
MINES: If a country has limited resources targeting this can have a devastating effect on the enemy. For instance, dropping a biological warfare agent on a copper mine could affect a great many things. Copper has an incredible number of uses from computer circuits to electrical wires.
OBSERVATION POST/STATION: This is a target that provides information to the enemy and can warn them of an impending attack. Observation posts/stations are primarily for monitoring enemy activities and are pulled back before they can be destroyed. Destruction of an observation post (without enemy knowledge) can increase the chance of surprising the enemy.
POWER GRID/STATION: Attacking this can effect the enemy in various ways. It can have a demoralizing effect on the enemy’s civilian population who might put the pressure on the government to end the war. If the enemy’s technology allows the transmitting of power ‘over the airwaves’ it can severely curtail his/her military operations.
REPAIR FACILITY: Destruction of a repair center can seriously hamper the enemy’s ability to return damaged units to the front lines. It might also prevent the enemy from building new units.
REPLICATORS OR FACTORY: This objective can be critical in a war because of what it produces. In World War Two for instance ball bearing factories were a high priority target because ball bearings had so many uses, from airplanes to tanks.
RESEARCH/SCIENCE STATION: Destroying a science station can slow down or halt enemy research into a certain subject. It could also prevent the enemy from discovering an important event that would effect them.
SEA VESSEL: Attacking a sea vessel can have many purposes, from rescuing hostages to collecting intelligence material or supplies.
SENSOR SITE: The destruction of a sensor array can limit an enemy’s ability to gather information in a timely manner. For instance, a Sensor site can detect starships in orbit, or deep space and transmit targeting data to other weapon systems that can reach it. One sensor site can direct a multitude of weapon emplacements. For example, a radar site can inform higher command of enemy air movement so fighter craft can be launched or sent to investigate.
SPACEPORT FACILITIES: Depending on the technology level an attack on a spaceport can severely damage a local economy, or the enemy’s ability to evacuate, resupply, or reinforce local troops. If the enemy uses something like anti-gravity ground to space and space to ground shuttles then spaceports have less strategic value. Destruction of spaceport facilities can also hamper an enemy’s ability to repair and build starships.
SPACESHIP: The reasons for attacking a space ship are nearly endless, from hostage rescue to capturing it and using it to attack the enemy.
SUPPLY/AMMO DUMP/FUEL DEPOT: Attacking a supply center can be a disaster for the enemy. If the supply center is destroyed then the enemy will very likely experience shortages until the material in the center is replaced. This can cause attacks to falter or cause the enemy to retreat from his defensive position.
SUPPORT VESSEL: Destroying a support vessel, be it a spaceship or an ocean vessel, can cause a great deal of hardship on enemy forces. Destroying a vessel full of supplies can severely hinder enemy activity and destroying a gunship will do no less.
TERRORIST TRAINING CAMP: This target is usually inside the national boundary of a country that is not currently at war with the attacker. This kind of objective must be attacked with care to avoid a war.
TRAINING FACILITY: This target can effect the quality of the enemy’s training and demoralize troops that have not yet faced the enemy. Fresh recruits who have not been fully trained can be scarred psychologically by the attack and when they do finish training they can affect the units they are sent to.
TROOP STAGING AREA: Attacking a troop staging area can spoil an attack and demoralize the enemy who is preparing for an operation.