Bullseye (online game) alpha

Sandbox to train refactoring the code with "callback hell" to cleaner one using Promises of ES6 standart.

Updates 2/15/2019:

• ES2015 modernized to ES2017 (Async functions added);
• Responsive layout ensured;
• Improved logic of the game.

Updates 2/12/2019:

• ES5 modernized to ES2015 (Promises added);
• Copyright script and styles updated.

Features:

• CSS animation "Rainbow Loader" created by Avan C. and published at https://codepad.co/snippet/3SuRP9Xh;
• HTML5, CSS3, and JS(ES6).