Need Help with Combat Mechanics!

OK -

Question 1: Defense should be static for your heroes just as it is for your monsters.

Think of it this way:

When you attack, you are taking a weapon, thinking actively about overcoming any defensive maneuvers of your opponent, applying a skill set, and physically manipulating it based on all of these. Your opponent is either taking the hit to armor or themselves, dodging, or getting missed. The three options for the defender are LARGELY based on the choices of the ATTACKER.

That said, I would assume that as with the other systems, bonuses based on the attributes (CHARISMA, STRENGTH, DEXTERITY, etc...) are at a certain level because they are INNATE attributes. This would mean that if someone threw a rock at someone with a dexterity of 5, they are not as able to move out of the way, or clumsy and oafish, or don't know how to gracefully take the hit of the rock in a way it won't hurt them. But someone with a dexterity of 20 would EASILY be able to dodge the rock - WITHOUT A DIE ROLL TO CHECK WHETHER THEY ARE ABLE TO, because by the nature of an attribuite, they have a 20 basically because they are JUST... THAT... GOOD!

If you needed them to, say, jump from rooftop to rooftop while chasing a thief, however, you WOULD need to roll to see whether the dexterity 5 or the dexterity 20 hero made the jump without being affected by falling rooftop tiles, landing funny, excessive wind, etc...

SO, the defense should be a static value based on the armor of the defender, but should be allowed to be modified by attributes STATICALLY. Assuming attributes of, say, 15 being moderately good, strength can mean you are not as damaged by hits, so a +1 to defense, dexterity means you can take hits gracefully to reduce damage, and dodge most others, so +3 to defense, intelligence over, say, 20 might get a +1, simply because you can think of defending WHILE attacking, so a +2 on defense, etc... add these to the armor you are wearing with a defense of 6, and your defense starts at a STATIC 12, regardless of the attacker against you.

Rolling on defense will confuse the game, and allow for more debate as to the quality of the rule-governing system, "well, I should ALSO be able to roll a d6 to see if my guy can duck and roll into combat so he can't get hit before he attacks..."

Your heroes KNOW they are able to be hit by opponents, and they have prepared themselves mentally and physically for this in their armor and attributes. Their opponents presumably have also. Treating them differently would be counter-intuitive.

Question 2: To simplify damage, yet leave it dynamic enough to be interesting, you SHOULD have different weapons be worth different damages (if I hit you with a bamboo staff in the face, you'll most likely live, but if I do that with a sledgehammer, well...)

BUT, the amount of damage should also be based on the DIFFERENCE between the "to hit" and "defense" rolls.

If your opponent has a defense of, say, 5... and you have a warrior that rolls a 3 on his d10, and a 5 on his d12, he hits. but if he rolls a 10 on his d10 and an 11 on his d12, is a 21 against a 5 the same as an 8 against a 5?

It shouldn't be, otherwise, why don't you just have "yes" and "no" labeled on certain sides of the dice, and count up who gets more "yes" rolls? mainly mecause you want the experience to be based on a SCALED RANGE OF VALUES THAT REPRESENT SOMETHING REAL.

The 8 should represent a glancing blow, while the 21 should represent a square hit, possibly knocking the opponent down... (this also makes the prospect of "awesome" die rolls exciting, and actually rolling them satisfying to the players...)

so, damage should be a static weapon value, but should also be, say, +1/4 (you can tweak it during testplay...)for each point in the difference between the rolls... (rounded up/down at DM's discretion...)

so, with a warrior's weapon with a damage of 7, the 8 against the 5 would be worth 8 points of damage, (7 + 3/4 = 7.75, rounding to 8...) and the 21 would be 11 points of damage (7 + 16/4 = 11). static modifiers from attributes like strength and vitality and possibly skill with the weapon they're using may also apply...

Question 3: HAHA... that's a question LOTS of people ask about their own game design... as with any product, most of what you're doing will not be COMPLETELY original... the key that makes that question not matter (barring any copyright/trademark infringement, of course) is this:

Is what you made original in CONCEPT, or THEME, or does it have even ONE dynamic or mechanic that (even if it isn't an original dynamic or mechanic) makes your gameplay different?

If so, then it doesn't matter what people say about what they think your game is BASED ON, you've modified it to be your own, and as long as you don't DIRECTLY rip off these things, or blatantly just use pieces of other games, it can be considered an homage to the genre of RPGs in general.

Think about the sheer number of RPGs that exist... ALL of them have to have the kind of mecahnics you've described, but have tweaked them in some way to make them somehow their own entity... what happens of leather-clad, horse-riding warriors traipse in on a mutant zombie-infested technology-driven wasteland? the possibilities are relatively endless, but the point is simple... people combine mechanics all the time, and come up with the same ideas miles apart, with no knowledge of each other, and AT RELATIVELY THE SAME TIME, sometimes... it doesn't mean you're stealing ideas unless you feel you are (or it can actually be PROVEN that you are...)

So, I wouldn't worry about question 3.

One thing I'm thinking about when reading through this is your use of the term "heroes" (for Player Characters (PCs)). It seems like you want this to be the focus of the game - that the players are controlling heroic individuals, destined to be greater than others, and that they have some sort of edge or advantage as a result. This could end up taking many forms, such as ties always going to the PCs, the PCs always making the rolls (vs static attack or defense values for NPCs) and therefore keeping them engaged, to introducing the concept of possible automatic successes for very powerful characters, to keeping play fast and fun.

Some things you could consider (some based off of previous comments) if this is what you are looking for -

- combining attack and damage into a single roll. Roll #dX + Stat to attack. If this beats the static defense, damage done is equal to the difference between the two. To prevent this from getting out of control, the types of dice being used and stat modifiers can be manipulated to reflect different types of attacks. A d12 has an average roll of 6.5, but 2d6 has an average roll of 7. However, it is much easier to get a 12 (or 1) on a d12 than a 12 (or 2) on 2d6.

- with the above, you could add extra damage when the max value on a die is rolled, such as doubling the value of a die, adding a fixed amount, or doubling the entire result. This could allow for the increased possibility of critical hits when rolling multiple low score dice, vs rolling a single large score die.

- to reflect high toughness, low mobility creatures, a secondary score of "toughness" / "resiliance" could be introduced, providing a fixed modifier to the damage done after an attack. This could exist for PCs as well, and be based on their Vitality (always gets hit, heroically shrugs it off)

- have it possible to always succeed at a task. When the target value of something can always be achieved (for example, 2d4+5 will always be 7 or greater), then it always succeeds. The only time to roll would be if there is some benefit to having a higher number. The high dex heroic character will never have to roll to walk along a ledge. But the low dex cleric might. However, because there could be a range of outcomes from different attack rolls, players would always need to roll, even if success was guaranteed. If combined with success ranges / tiers (as per Jarec's comments), this could be translated directly to the calculated success tier.

- consider simplifying your stats. Something I've got in my notes for an arena combat game would be to use stats with numbers that would directly convert to roll modifiers. So a strength of 3 always adds 3 to strength related rolls. A dexterity of 8 would always add 8 to dex rolls.

- weapons could use strength or dexterity for attacks, depending on the weapon.

- you briefly mentioned a role playing aspect to the game. I'd recommend opening up your classes a bit if this is the case, and splitting race from class. Not all dwarfs are the same, not all elves are the same. Likewise tie damage to the weapon, not the class. Class should impact what you can do. So, maybe only rangers can use bows, but the bow defines the damage, not the fact that they are a ranger. EDIT - but, if you are aiming for fast and simple, you can keep some of this really basic - like, extreme limitations on what you can do based on class. In retrospect, that was probably what you were trying to do with the race = class thing, though from a role playing perspective, that doesn't really jive for me.

I'm new to this, so I can only offer my opinion. I wouldn't worry too much about the game mechanics being original. I kind of prefer it when I can glance at combat rules and say, "Oh, that's just like _____". It makes it easier to teach, and I get to play the game faster. The story element is what makes or breaks it for me.

You could keep the crits in check by requiring they role be the highest value on all the dice being rolled.