While a PC can do anything they might reasonably accomplish in six seconds as their Main Action for a round, some choices are more common than others. Below are a list of some of the tactics or actions that come up most often in combat.
Make a Melee Attack
Main Action
The combatant attacks an enemy within melee range, rolling a normal hit roll and inflicting damage on a successful hit. Most melee attacks inflict Shock damage on a miss, if the target’s Armor Class is low enough, and no successful hit does less damage than the weapon’s Shock would have done on a miss. An attacker’s weap-on must be Readied in order to attack with it.
Make a Ranged Attack
Main Action
The combatant fires or throws a Readied ranged weap-on at a target. The combatant can’t Make a Ranged Attack with a two-handed weapon if there’s a enemy armed with a melee weapon within melee range; it’s too easy for the assailant to bind up a rifle-sized gun. One-handed ranged weapons and thrown weapons can still be used, albeit at a -4 penalty to hit.
Make a Snap Attack
Instant Action
A combatant with a Ready weapon can rush their attack, sacrificing accuracy for speed. The combatant must still have their Main Action impending or available. As an Instant, they can sacrifice it to Make a Melee Attack or Make a Ranged Attack against a foe in range, whether a snap shot with a pistol or a quick thrust at an adjacent melee foe. This attack takes a -4 penalty to its hit roll. If multiple combatants decide to make Snap Attacks at the same time, they are resolved simultaneously.
Snap Attacks are usually made only by the desperate, the undisciplined, or the elite, and the GM should rarely have NPCs employ them. Untrained hooligans might blaze away in excitement or panic, or a gunman being charged by a howling spearman might risk a shot before he gets too close, but most combatants can’t af-ford to take such a heavy penalty to their hit roll. Truly skilled combatants, however, can sometimes get away with such risks, particularly if they have a Warrior’s class ability to turn a miss into a hit.
Total Defense
Instant Action
As an Instant action, the combatant focuses on nothing other than avoiding knives, gunfire, hurled crystalline spears, or other perils in the vicinity. Using Total Defense costs the user their Main Action for the round, and cannot be used if they’ve already employed their Main Action. They become immune to Shock damage for the round from melee weapons, regardless of their Armor Class, and gain a +2 bonus to their Armor Class until their next turn.
Club Up a Weapon
Move Action
A combatant can shift their grip on a Readied rifle or pistol, using it as a crude melee weapon rather than a ranged weapon. Rifle-sized guns used this way count as a medium primitive weapon with no Shock score, and pistol-sized guns count as a small primitive weap-on with no Shock score. Rolling maximum damage on a hit with such improvised weapons will break them. This action can also be taken to unclub a weapon and ready it to shoot.
Run
Move Action
The combatant moves their normal combat movement rate, which is 10 meters for most humans. If they’re climbing a surface, swimming, or navigating extremely rough terrain, this movement rate is halved, and they might have to make an Exert skill check to achieve even that. Prone characters crab along at half this rate.
Fighting Withdrawal
Main Action
The combatant disengages from any melee foes around them. They don’t actually move away, but they can now get away from their assailants without giving them a free melee attack. Usually, this means the combatant uses their Move action to get clear, because if they just stand there the enemies might choose to re-engage them the next round.
Use a Skill
Main Action
The combatant uses a skill that could be plausibly applied in a few seconds. An Int/Heal or Dex/Heal skill check to stabilize a wounded comrade is one such potential use, as is executing a pre-programmed hack, shouting out a stirring rallying cry to timorous NPC allies, or anything else that might be done quickly.
Ready or Stow an Item
Main Action
The combatant draws a weapon, extracts an item from their backpack, digs a magazine out of a belt pouch, or otherwise moves an object around on their person. They can Ready an item this way or Stow it.
Reload a Weapon
Main Action
The combatant swaps a Readied power cell or magazine into their weapon. Some very primitive firearms might require more than one action to load them, while an archer can nock another arrow as a Move action.
Drop an Item
Instant Action
The combatant drops something they’re holding. They can do this Instantly at any time to free up their hands.
Pick up an Item
Move Action
The combatant can scoop an object off the floor if they have a free hand, leaving it Readied in their grip.
Stand Up
Move Action
The combatant gets up from a prone position. Most characters that have just been revived from unconsciousness must get up before they do much else.
Go Prone
On Turn Action
The combatant falls flat, forcing distant ranged attackers to take a -2 penalty to hit them. Adjacent enemies find you an easier target, however, gaining +2 to hit.
Hold An Action
Move Action
By choosing to Hold An Action, the combatant can delay taking the rest of their actions until later in the round, activating them as an Instant action. Thus, a hero who wins initiative might use their Move action to Hold An Action. Later in the round, as an enemy rushes around a corner, he may Instantly elect to use his Main Action to Make A Ranged Attack with his readied laser rifle. If acting in response to someone else’s impending action, the held action is resolved first.