Unity is an integrated authoring tool for creating 3D video games or other interactive content such as architectural visualizations or real-time 3D animations. wikipedia.org

Game design, a subset of game development, is the process of designing the content and rules of a game in the pre-production stage and design of gameplay, environment, storyline, and characters during production stage. wikipedia.org

Game development is the generally involved and lengthy process of creating a video game. Development is undertaken by a game developer, which may range from a single person to a large business. wikipedia.org

An illustration is a displayed visualization form presented as a drawing, painting, photograph or other work of art that is created to elucidate or dictate sensual information (such as a story, poem or newspaper article) by providing a visual representation graphically. wikipedia.org

Bootstrap is a popular HTML, CSS, and JS framework for developing responsive, mobile first projects on the web. wikipedia.org

PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. wikipedia.org

The front end is responsible for collecting input in various forms from the user and processing it to conform to a specification the back end can use. The front end is an interface between the user and the back end. wikipedia.org