ALLIES FIGHTING WITH YOU - When fighting with allies, each attacker gains +1 to hit per ally actively fighting with them, to a maximum of +4 (kung fu and melee attacks only; ranged attacks get a flat +1 and no more).
ATTACKING FROM BEHIND - You cannot defend from an attack from behind unless you have the quality 'Situational Awareness'. In which case, you may defend, but at a -2 penalty. At staff discretion, would-be victims may get a Perception + Notice roll, and if successful, may also defend with a -2 penalty.
DRAWING A WEAPON - Pulling out a weapon generally counts as one action. However, the Fast Draw maneuver, Fast Draw as a Wild Card skill, or gadgets that load weapons automatically such as Angel's spring loaded stake dispenser can negate the one action requirement.
FULL DEFENSE - This allows the character to defend from two attacks at no penalty, as well as other attacks with the normal penalties applied. They gain a +3 to all defensive actions (ie, the first two attacks in that Turn at a +3, the next attack at a +1, no mod on the next attack, -1 on the next attack, etc until the end of the Turn). No attacks may be performed during a Turn declared as Full Defense.
FULL OFFENSE - The character gains a +2 to all attacks during the turn, but may not use any defensive maneuvers.
KNOCKDOWNS AND FIGHTING WHILE LYING DOWN - When a character is knocked down, they cannot attack for the remainder of the Turn. They may defend at a -4 penalty, and as long as they are on the ground, any attacks and defenses they attempt incur a -4 penalty. It takes a Turn to get up, though with at least two SLs on a Dexterity + Acrobatics roll can shorten that to an action. Any maneuver that states it results in a knockdown, and any blow that inflicts more than triple the victim's Strength in damage before accounting any modifiers results in a knockdown (if it seems dramatically appropriate).