So the basic premise of Runic is to collect runes. To keep the idea simple I'm going to keep this idea to four basic runes for now, one for each stereotypical element (earth, fire, wind, water). Cliche but it works. Once all four runes are collected the character must dive into the void to either free some deity that will save the world or imprison some evil deity that's trying to destroy it. I haven't worked out which yet but I guess the later would give some big bad guy so that's probably the better route to go. So player collects the four runes which lets him open the gate to the void (plane of emptiness/darkness) where he confronts the big bad on his home turf and (hopefully) defeats him.
Now the actual element of collecting the runes will work like megaman. You start the game with no runes and decide which plane to tackle first. Some planes may be nearly impossible without first visiting another plane. For instance the fire plane may deal damage to you each turn without some form of protection provided by a water rune (preferred method) or an air rune (not quite as good but still workable). In addition to runes the player will also be able to find gear as they go along, much like any typical roguelike. The gear will further augment their character and possibly allow them to tackle planes in an order they wouldn't normally based on what gear they found (a helmet of water breathing for instance may make the water plane doable before the air plane).
Runic casting itself will have its own mechanics. Basically once you get a rune you have it but you must power them up by using them. In other words, when you get the fire rune you may have access to fire bolt. For example, once you cast fire bolt ten times your fire runes power will increase by one, which will increase the power of your fire bolt and unlock the level two rune power (we'll just say it's fireball for now). Once firebolt is cast another twenty times or fireball is cast ten times runic power will again increase by one and so on and so forth until the rune reaches maximum power.
Of course, we'll need a balancing mechanism for this. So we'll put the runes together in sort of a box or circle. Increasing the power of a rune will decrease the power of the opposite rune by a like amount. So raising fire runes power up by one will lower your water runes power level. The maximum runic power of all runes will be equal to twice the number of runes the player has and the base power level will be equal to half this amount. At any point the player will be able to rebalance their runic power and collecting a new rune will automagically do this.
So basically once you get your first rune your runic power raises to one with a max of two. When you get your next rune all runic power resets to two and your max becomes four and so on and so forth. Rebalancing runic power will probably have some super effect based on the current balance of power (having high fire for instance may require you let out a burst of water around you to rebalance your runes).
Obviously the idea has a long way to go and still needs a lot of fleshing out. But the above is the basic premise anyway. I'd kinda like to do something with a light and dark rune too just because I have some neat ideas for powers (like a darkness walk or increasing light radius to make the plane of darkness more bearable). So maybe six elements? Maybe the Void could be more of a metaphysical everything and nothing plane (though it may need a better name then that).
*edit* I forgot to mention, the runes will also work kinda like sustains. The higher the runic power the more and better intrinsic abilities you'll get (having air at power level two for instance may give you a constant air bubble that surrounds you, at higher levels it may give you flight).
