Check out Traditional OOP Inheritance in JavaScript
The above blog post may help answer some of your questions.
It elaborates particularly on defining a new constructor for an object, which "inherits" from a parent. Is that one of your questions? Take this for example:
NamedRoundedBlock.prototype = Object.create(
Block.prototype,
{
"constructor": {
configurable: true,
enumerable: false,
writable: true,
value: 'NamedRoundedBlock'
}
}
);
The above created an object based on Block's prototype, but it defines its own constructor, and also sets it as not enumerable.
Also, should the first line be something like this?:
function NamedRoundedBlock() {
this.name = this.makeFeild("name");
//etc.
Additionally, independent of the issue, I'd be careful with the spelling of "Feild" (spelled "Field"), as spelling issues can sometimes cause hard-to-find bugs later in the code.