The ES6 - JavaScript Improved course on Udacity offers a comprehensive guide to the latest features of JavaScript. The course begins with an exploration of new syntax, teaching students how to define variables in new ways, use destructuring for efficient work with arrays and objects, and introduces a new method for looping using the for...of loop. The course then delves into functions, demonstrating how to write cleaner, more concise functions using arrow functions, understanding the behavior of the this keyword in arrow functions, and exploring new methods for creating extendable JavaScript classes and subclasses. The course also covers new built-in features, allowing students to experiment with new object types such as Sets, Maps, WeakSets, and WeakMaps, handle asynchronous requests using JavaScript Promises, and learn how generators can pause the execution of a function while maintaining its state. Lastly, the course equips students with professional developer skills, teaching them how to write ES6 code for unsupported browsers using polyfills and transpilers, and how to use a transpiler to convert ES6 code to ES5 code.