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

A casual game is a video game targeted at a wide, mass market audience, as opposed to a hardcore game, which is a game targeted at a more niche audience of hobbyist gamers. Casual games may exhibit any type of gameplay and genre. wikipedia.org

Roblox is a game creation platform which allows players to create their own games using its proprietary engine, Roblox Studio. wikipedia.org

Graphic design is a creative process - most often involving a client and a designer and usually completed in conjunction with producers of form (i.e., printers, signmakers, etc.) _ undertaken in order to convey a specific message (or messages) to a targeted audience. 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