• Being unable to see your target causes you to suffer a -1% to hit per 2% of concealment, to a maximum of -50% to hit if you cannot see the target at all. In such cases, you must somehow know which square to attack.

The most basic of modifiers.

• For each square of distance between you and your target, you suffer -1% to hit.

As the attacker, your own movement makes it harder to hit.

• Taking a single move action imposes a -10% penalty to hit for the remainder of your turn.
• Taking a double move or charge action imposes a -25% penalty to hit for the remainder of your turn.
• Taking a full run imposes a -50% penalty to hit for the remainder of your turn.

Normally, enemy movement is not a factor. However, an enemy may choose to "run evasively", a normal move action which imposes a 50% movement penalty, but also imposes a -25% hit chance to ranged attacks against the enemy.