requirejs unable to find module returning undefined - requirejs

Question

i've been working with require before, but never ran into this issue,
maybe i got a path wrong somewhere but this is my filestructure:
js
├───main.js
│
├───app
│ ├───app.js
│ ├───hello.js
│ ├───world.js
│ │
│ └───models
│ └───game.js
│
└───vendor
├───jquery.js
└───require.js
main.js
require.config({
paths: {
'jquery': '../js/vendor/jquery'
},
shim: {
'jquery': {
exports: '$'
}
}
});
require(['app/app', 'jquery', 'app/models/game'], function (App, $, Game) {
console.log(arguments);
$(function () {
console.log('why is my App undefined?', App);
App.init();
});
});
app/app.js
define('App', ['hello', 'world'], function (hello, world) {
var App = {};
App.init = function () {
alert(hello + ' ' + world);
};
return App;
});
the code fires alright, however my dependencies seem to fail on app or hello or world module, App logs as undefined, so does my game module.
app/app should be the right path to my App module or am I thinking that wrong?
Update
I thought the capital A for App fixed the issue (but at the same time I took a swing at Jlange's comment, so I fired up the app/App module from the index.html. Which seemed ok, but after continuing the development it came up again.
I can load every module in the same directory just fine, but I cannot modules from subdirectories.
like the initial example couldn't load app/App from within the Main module, so can the app/App module not import the models/Game module.
I literally have no clue what this can be, as I said before, I have worked with requirejs and have not run into this issue.
Update 2
I can make it work if I drop all the named modules,
define([dependencies], function (dependencies) {});
that works fine
but as soon as I change it into a named module I cannot find it
define("moduleA", ['subdir/moduleB'], function (moduleB) {
console.log(moduleB); // >> undefined
});
define("subdir/moduleB", [dependencies], function (dependencies) { return 'B'; });

Answer 1

edited
after many tries, to fix the above code, and reading up in the requirejs help pages, I found a small passage, saying it is best not to use named modules and let the optimizer name them for you.
So I decided to remove all module names
moduleA.js
define(['subdir/moduleB'], function (moduleB) {
console.log(moduleB); // >> 'B'
});
subdir/moduleB.js
define([dependencies], function (dependencies) { return 'B'; });
this works just fine...
don't know how I got fixed on using those moduleNames, Thought it would be better to name your modules.