So the 'save' system is a chance to resist effects from any number of sources(spells, traps, you name it). The fun part here is that in order to be at all effective, you have to try and balance out your saves so they are all at roughly the same level. Let's say you get three tapes of saving throws:
The way they work is when you get hit with something, the system makes an RNG role(probably a percentage) and then adds your save to it. Then it subtracts the difference between that save and the other two saves.
Let's say your saves look like this:
- Will - 31
- Magic - 25
- Fortitude - 26
And you run into a trap. For the sake of this example, let's say traps are fortitude-saves and you're trying to beat a 50. The computer generats a number between 1 and 100, then adds 26 for fortitude, then subtracts 6. Over all that's not half bad, the saves still matter and there's still a good chance you beat it.
But now let's see it scale. At higher level, your saves look more like:
- Will - 75
- Magic - 106
- Fortitude - 55
The computer still roles, but this time it subtracts 71.
The reason for this system is it creates another area for gear and build to consider. You have to keep your saves all in roughly the same ballpark. So let's say you find an item that looks really good, but it happens to have +50 to Magic Saves. It's going to be a challenge to slot it, you have to find a way to either decrease that or increase something the others.
This could also be a boon to the perk system, design perks that help even it out more, maybe give the option of cutting three categories into two("You use your Fortitude Save for Will Saves and subtract only the difference between Fortitude and Magic").