So I am thinking about how to implement the combat system in my RPG, thought I might run some ideas past the crowd to see if they are sensible / stupid. It's fairly basic at the moment, want to get it working before making it more complex!

(Oh, should mention: there is no hand-to-hand (or sword-to-hand) combat in my game, it's not about swords and dungeons, so basically just about everything can be classed as "magic")

I'd like to consider each "spell" - I call them "ability" - as being a synthesis of traits. A "trait" consists of a type of attack (might be "fire" or "electricity"), and a skill level at that. So for example a hand grenade might have the traits {physical,fire} and so the damage it inflicts will be a combination of the damage from the individual traits.

I intend to implement "luck" in a slightly different way from what seems to be standard. Basically I will consider luck to be 100%-skill. Luck will shift the computed damage around. At low luck levels (ie high skill levels) rather than having a symmetric normal distribution (or far worse, uniform), the distribution will be skewed so that a boost of some percentage is much more likely than a cut. At low skill levels, the skew in the distribution flips - you are more likely to reduce the computed damage. At 50% luck, the distribution is effectively normal and symmetric.

Doing damage (or healing, or winning a battle, or...) gains players experience points, and those EXP eventually yield players tokens to upgrade their skill level in particular traits ("Child of Light" style in a graph). Each player in the team has a slightly different multiplier for exactly how much their skill increases when they buy a token for it (the trait "affinity") as well as a personal maximum for that trait. So although each player can develop any skill, it will pay to consider their skills.

Big question I'm starting to ponder: given a set of mechanics, how does one determine the order of upgrade nodes in the development graph(s)?

>> how does one determine the order of upgrade nodes in the development graph(s)?

are you referring to the unreal engine?

Oh no, I mean that there's a graph of nodes that a player traverses (see Child of Light / Final Fantasy X), whereby each time you hit a node you are conferred some upgrade to your stats or skills. In the Child of Light system you are granted tokens, you can move a node on for every token you obtain.

To know what path your players should take, I think, you need to have an idea of the destination. Do you have a final battle of some sort in mind? Do you have an idea of how powerful or what abilities you want your players to have when they reach the end? Will there be a few key abilities or items that the players will need to be able to finish the game?

Lots to think about! Thanks for the help so far. This is clearly going to take some iteration to get right. My instinct is to get a "simple" system going and see how it works in practice.

One of my ideas for the game is to have a single common "MP" bar for all the goodies. This will take the place of both MP and to some extent money, and will add an element of resource management.

I am now very much leaning towards a "Child of Light" style upgrade system where battles earn you exp, exp levels you up, levelling up yields a number of tokens that moves you along a path in the Tech Graph. Most basic nodes allow a +1 trait increase, but I am thinking that I might make the Tech Graph a sub-game in itself - think Monopoly but with tokens up for grabs.

Thoughts?