I've been lurking for awhile now and have come to respect the feedback offered by members of this forum. Because of this I decided to post the combat system for a RPG game my friends and I have been playing for years. It's been played in one form or another for 15 years now but I've never shared the rules with anybody outside of our group. Recently though, I've been considering trying to publish the game and am interested in some feedback from folks who don't know me.

The system is percentile based but lately I've pulled in some aspects of the One Role Engine that I liked.

I would gladly post the entire thing or email it to anyone interested but it's 13 pages in length so in the interest of legibility I'm only going to post part of it here. Some of the formatting did not transfer to this post well so if it's too long, too unreadable, or just plain boring feel free to not read it.

ATTACKING

Chance to Hit
For any given combat strike, a combatant has a specific chance to hit his or her target successfully.  Well, at least that’s the formal way of saying it.  In the interest of conserving manual space (too late) and playing time, we usually resort to more concise jargon.  Questions such as, “What is your specific chance to hit your target successfully?” become “What’s your chance to hit?”  Lonnie, even makes lavish use of the tiny, “To hit?”  And, in fact, we most frequently refer to this success chance as “to hit.”

 To hit must be rolled each time a strike is attempted.  When in combat, this to hit chance is based on the attacker’s weapon proficiency skill with whatever weapon is wielded.  As with virtually all else in Battlecry, to hit is expressed as a percentage; the higher this number, the better the combatant’s chance with that strike.  The process of calculating a to-hit chance is tho-roughly explained below.  And boy, do I mean thoroughly.  

Note that when attacking with something that does not fall into one of the weapon groups, the GM should fit the item into its closest weapon group.  Some such items are:  chairs, dirty goblets, broom sticks, frying pans, rolling pins, and so on.  (Hey, most of those are food-related items. Weird.)  Each of those weapons would fall into the “blunt weapons” category; a broken bottle would fall under daggers, a long pointy stick would fall under pikes, and so on.  Stretching our imaginations, a garrote would fall under unarmed combat, and a lasso would fall un-der thrown weapons.  Most other stuff will be qualified as a blunt weapon; again, it is up to the GM to make these judgment calls.

For game purposes, a missile weapon is any-thing that is thrown or fired at a target.  Exam-ples of missile weapons would be: a rock thrown at an opponent, an arrow fired at an enemy, a spear thrown at an opponent, etcetera.  Any melee weapon that is thrown or fired is treated as a missile weapon, and the character figures his chance to hit accordingly.

Chance to hit when not in combat
 When characters wish to strike a target in a non-combat situation, the action should still be funneled through a weapon group (or unarmed combat, if applicable) to determine success chance.  For instance, a thrown weapons roll is made when a character attempts to throw something to another character, when a grappling hook is thrown, when a character wants to skip stones, and so on.  Unarmed combat would be consulted when one character attempts to grab another to keep her or him from falling, or when the faller attempts to grab something to stop the fall.

When Attacking
 Before any to-hit dice are rolled the attacker must state at least the following tidbits of information.  Is the attack targeting a specific strike location, and if so which one?  What weapon is the attacker using?  If unarmed combat, is it going to be a grapple, a throw or a strike?
 An attacker is not required to target a specific strike location. If a strike location is not targeted the hit is treated as a torso hit (no modifiers to damage).

Base Chance to Hit
 To determine an attacker's chance to hit with a weapon, first determine which weapon proficiency skill is required.  If the weapon being used is covered by a weapon proficiency skill simply utilize the number on the character sheet.  If the weapon being used is not covered by a weapon proficiency skill, the success chance is calculated as per any skill that the character does not have (that is, by using half of the character’s base chance with that skill).

 For an attacker to use the weapon proficiency skill the weapon must be used in the correct manner.  So if an attacker has the weapon proficiency skill with swords and throws a longsword, the thrown weapons skill must be used instead.

 An attacker may also receive bonuses with a weapon or unarmed combat from a few other areas besides his or her skills.  A magickally-enhanced, or a finely-crafted weapon that gives bonuses to unarmed combat are the most common examples of this.  Penalties could also be given to a character due to a cursed weapon or a weapon of lesser quality.  These modifiers are applied directly to the character’s chance to hit (not to the die roll).

 The number arrived at above is termed an attacker's base chance to hit.  The players should be sure to record their base chances to hit with all weapons on their character sheets.  This will simplify things for the GM and speed up game play.

Target modifiers
After determining an attacker's base chance to hit with the weapon being used there are target modifiers to apply.  Target modifiers include the strike location and any modifiers to be hit from magickal items the target might have.  

 If the number is negative, deduct it from the attacker's chance to hit.  If the number is positive, add it to the attacker's chance to hit (again, NOT to the die roll).

Strike location is simply an area of a humanoid body.  Any attacker may choose a specific strike location before any "to hit rolls" are made.  If the attacking character doesn't specify that they are aiming for a specific strike location, the GM should always consider the hit a strike to the torso (since all other strike locations have penalties to hit and modifiers to damage).

There is also a negative modifier associated with all of the strike locations, except the torso.  
 The following table lists all possible strike locations and the penalties associated with each location.  The GM will have to improvise for Creatures and Beasts that do not completely conform to the humanoid body locations table.

Strike Location Table
Body Location Damage Bonus To Hit Penalty
Head                      X2               -50
Neck                      X3                 -75
Torso                      X0                       0
Abdomen               X2                 -50
Legs                      X0                        -25
Arms                     X0                   -25

Block and Dodge modifiers
Since nobody likes to be hit, we’ve given de-fenders the option to block or dodge attacks. A successful block or dodge roll will give negative modifiers to an attacker trying to hit the defender.  (For the complete rundown on blocking and dodging see below we are only interested in the attacker’s viewpoint in this section.)

 The modifier is equal to the defender’s block or dodge skill (whichever was used) divided by 3 (round up). Shields give a bonus to a defender’s block modifier depending on the size of the shield. This in turn deducts more from an attacker’s chance to hit.

1) Small shield +10 block modifier
2) Medium shield +20 block modifier
3) Large shield + 30 block modifier

Situation Penalties
Situation penalties are totally optional and as such need not be used.  If they are to be used, the GM will need consult the following table to determine if and when any situation penalties apply.  These penalties are applied to an attacker's base chance to hit.
 
This section attempts to cover all other penalties that might affect a combatant's chance to hit an opponent.  No section trying to cover so much material is ever going to be complete, so for now we will try to keep things as basic as possible..  Whenever one combatant tries to strike another, refer to the tables below to see if any of the penalties apply to the situation.  All penalties are cumulative.  If no penalties apply, the GM is not trying hard enough.

Situation Penalty Table
Action/Situation To Hit Penalty
Attacker charging -25
Defender charging -25
Defender has reach -50
In a confined space -50
On a moving horse -75
On a non-moving horse -50
Target 1/2 attacker's size -25
Target unseen -75
Too close for weapon -50
Using off-hand -50

Attacker charging:  The attacker is charging the defender (see charge rules for specifics on charging).

Defender charging:  The defender ended his or her last round charging his or her opponent.

Defender has reach:  If the defender's weapon is longer than the attacker's, or the defender is just much larger than the attacker, the defender is considered to have reach.  This makes it harder for the attacker to get in close enough to attack well.  Some common sense must be used here:  even if a Dwarf is wielding a broadaxe a giant wielding a dagger probably still has a reach advantage.

In a confined space:  A confined space is any space small enough to seriously hinder the attacker's action.  This can be due to the attacker's weapon being too large for the area he or she is wielding it in, or because the area is just too small for the attacker to move freely.

On a moving horse:  The attacker, or defender, is on a moving horse.  The horsemanship skill may be used to negate this penalty.

On a non-moving horse:  The attacker, or de-fender, is on a non-moving horse. The horse-manship skill may be used to negate this penalty.

Target half attacker's size:  If the target is half the attacker's height or smaller, the attacker has a -25 penalty to hit the target.  This only applies if the target is a living (and moving) object.  
Target unseen:  The target is hide-and-sneaking, invisible, or the attacker is blind, etc.

Too close for weapon:  If the target is closer to the attacker than half the attacker's weapon length, then the attacker is too close for his or her weapon to be used effectively.  Example:  Iggy is wielding a 7’ long weapon, but the target is only 3’ away.  One-half of Iggy's weapon length is 3 1/2’, so Iggy would receive a -50 to hit the target.

Using off hand:  This means the attacker is right-handed and attempting to attack using his or her left hand, or vice-versa.  This is obviously moot if the attacker is ambidextrous.

Rolling Against Chance to Hit
As mentioned earlier, an attacker's chance to hit is the percentage chance the attacker has to strike a target in combat.  To roll against this number simply roll percentile dice individually for every attack the combatant makes.  If the roll is equal to or less than the attacker's modified chance to hit, then a hit has been achieved.

DEFENDING

Contrary to popular belief, combatants do not have to use all of their actions for attacking, they may attempt to defend themselves.  In the Battlecry world, combat defense consists of blocking and dodging.  Any defender may attempt to block and/or dodge.

Blocking
Any combatant that is using a weapon, or has arms (that’s most of them), has a chance to block attacks made against his (or her) person.  Blocking costs one action.  

 A successful block roll allows the defender to deduct his block modifier from any successful attack rolls made against him. If this results in the attack missing he takes no damage from the strike.  
 
A defender’s block modifier is equal to his block skill divided by 3.

 Example: Aros Atuk has declared he is going to block this round. He rolls against his block chance of 60 and gets a 41, success!

 A bandit attacks Aros during the round. The bandit’s base chance to hit is 50. He now has to deduct another 20 though because of Aros’ successful block roll. The GM rolls against the bandit’s modified to hit chance of 30 and gets a 35, a miss

Another bandit (whose base chance to hit is also 50) attacks Aros and has to deduct 20 from his base chance to hit also because of Aros’ successful roll. The GM rolls a 26. Still a hit but not quite as severe as it might have been if the bandit still had his full chance to hit.
 
No distance attacks (from thrown weapons, bows and crossbows) may be blocked (except by a shield).  Distance attacks from thrown weapons may be dodged. Distance attacks from bows or crossbows may not be dodged.

The defender may only block attacks that come from attackers go after him in the combat round. Attacks whose SPD is higher than the defender and who chose to go before the defender may not be blocked or dodged.

Combatants may choose not to block an attack.
 
One combatant may attempt to block a strike that another combatant is the target of.  In other words if your friend is about to get hit you could use an action to attempt to block that strike. There are some restrictions to this (aren’t there always?).

1. The defender would need to state he is blocking attacks aimed at the other combatant that round.
2. The defender may only block attacks aimed at one person during a round. So either himself or one other person.
3. All normal blocking restrictions apply.
4. Use some common sense here, and remember that the GM has final say.

 Shields give a bonus to a defender’s block modifier depending on the size of the shield. This in turn deducts more from an attacker’s chance to hit.

1) Small shield +10 block modifier
2) Medium shield +20 block modifier
3) Large shield + 30 block modifier

  If there’s something that gives bonuses there are certainly going to be things that give penalties to a defender's block modifier.  These are situation penalties and, as with all situation penalties, are optional.  

 These are not all that could affect a combatant's chance to block; they are just some obvious suggestions.  If a GM wishes to add more, he or should feel free to do so; the attacking situation modifiers could certainly be used here as well.  All of these penalties are located below and again at the back of the manual.  (We strive to be redundant).  (We strive to be redundant).

 When applying a defender’s block modifier to an attacker’s chance to hit check the particular column of the table.  If any of the situations apply then deduct the corresponding penalty from the defender's block modifier – for that attack only.  All penalties are cumulative.

Blocking Modifiers
Blocking a heavier weapon -25
Fighting an opponent twice your height -25
Blocking non-proficiency weapon -25

Blocking a heavier weapon:  If the attacker's
weapon is heavier than the defender's weapon the defender suffers a -25 penalty to his or her block modifier.  This reflects the fact that a heavier weapon can be used to "beat down" an opponent's guard and make blocking harder.

Fighting an opponent twice your height:  If the attacker is twice the defender's height the defender will suffer a -25 to his or her block modifier.  This penalty is an attempt to show that a much larger opponent can use sheer size and weight to overcome a defender's guard.

Blocking a non-proficiency weapon:  Different weapons require different styles of fighting and this can cause difficulties when attempting to block them.  Anytime a defender attempts to block a type of weapon he or she does not have a proficiency with the defender will suffer a -25 to his block modifier.  Notice that this only applies if the attacker has a proficiency with the type of weapon being used.

Blocking and Unarmed Combat
A person using unarmed combat takes no damage from blocking a weapon, nor from her or his attack being blocked by a weapon.

Dodging
 Dodging may be used in lieu of blocking at any time; in addition any combatant may attempt to dodge. The Dodge mechanic works exactly like the block mechanic with a couple of notable differences.

1) You may not dodge an attack aimed at someone else.
2) You may dodge thrown weapons.

 Heavier armor deducts from a combatant’s chance to dodge. If wearing a combination of two types of armor use the modifier for the one on the torso and legs. If those are different, use the bigger modifier.
1) Reinforced Leather -25
2) Chainmail -50
3) Platemail -75

Block/Dodge Critical and Fumble Rolls
 During combat a critical roll when rolling versus block or dodge could give a bonus to the modifier. We suggest +25 to the defender’s block/dodge modifier but the GM can, of course, use whatever modifier is appropriate for his game.
  For a fumbled roll, the GM should consult the fumble table.  

DAMAGE

Determining Damage
Any successful strike may damage the target.  Determining how much damage is done is a multi-step process.

1) Find the weapon damages chart and cross-reference the type of weapon being used with the damage column to get a number.
2) Add the character’s STR score modifier to the weapon damage.
3) Add the damage generated from the strike damage table.
4) Subtract the armor modifier from the damage generated.
5) Apply any multipliers from situation modifiers.

 The first two of those are fairly simplistic so we won’t spend any further time describing those. Numbers three and four deserve a bit more explanation and so are described in all their glory below.

To Hit roll and damage
Deduct the attacker’s successful roll from his chance to hit to get the number of strike points generated then compare the final number to the table below. This is the amount of damage generated by the hit roll.

Strike Damage Table
Strike Points Damage
00-10 +1
11-20 +2
21-30 +3
31-40 +4
41-50 +5
51-60 +6
61-70 +7
71-80 +8
81-90 +9
91-95 +10
96-99 +15
100+ +1 per point

 Add the damage from the Strike Damage Table to the damage done by the weapon and the character’s STR score modifier.

The description really is too verbose (which is probably why people haven't replied to it - it takes too much time to read thoroughly, and I personally only skim-read it), and its use of large numbers seems almost completely unnecessary. You could have divided everything by 5, using a d20 instead of a d100 and it would have still worked just as well.

I'm skeptical about rules that take highly specific circumstances into account (e.g. the to-hit penality for being mounted), because rules aren't usually able to cover every single situation, but that's just my perspective.

Agreed. This is needlessly complex and long winded and offers no obvious advantage over d20+modifiers vs DC or d20+modifiers vs d20+modifiers.

Yeah, after I posted it I realized that it was waaay too long for folks to read in this setting. I do appreciate your feedback and have made some changes based on it.

Thanks again.