Sure thing, happy to help. In the context of a game it makes perfect sense to operate on the force values directly. Unfortunately you really cannot develop something like that without trying it on actual hardware.
1) What is the meaning of standard touch that will have 1.0 value? I mean the physical meaning, like is it basically the normal touch of average person without intention of pressing?
Yes, that's right.
2) How much force is the maximu force? Again, I'm interested about the feeling in the physical world. Let's say, will the maximum measurable force be able to break an average chocolate bar or does it max out on some lighter force? Is the force reported linearly? Can I assume that 0.4 is twice the force of 0.2?
That's a little bit like asking "how blue is the blue sky?" 🙂 From my completely subjective experience, it is a decent amount of force, one that I would characterize as intentionally pressing harder than a normal tap. These are exactly the types of questions that you need to have a device to experience it with. The details of the progression for the force are an implementation detail so you cannot make any assumptions about whether it's linear or not.
Depending on what you're trying to do specifically, you might want to come up with some kind of quantization of force similar to how peek and pop works. From my experience, this takes some trial and error to get right based on an app's interaction. Alternatively if you were trying to develop something that, for example, changed the radius of a pen based on the pressure then you wouldn't necessarily care about the actual values and rather focused on the percent of the max force. So it really depends what you're trying to accomplish.
3) Is 3D touch multitouch? Can I have readings from two touches simultaneously?
Yes, each UITouch has an independent force value.
