What is Unity
Unity is both a development environment and a game engine with which projects are created for different platforms: PC, mobile devices, game consoles, and Internet platforms, which is why it is called cross-platform. Unity has tools for creating objects, moving them, working with graphics, textures and sound, so you can even make a full-fledged game with it alone.

A prime example of a Unity game that supports multiple devices is Genshin Impact, a successful multi-platform project from Chinese studio miHoYo Limited. Its mobile version has become more popular, but users can log into their account, for example, from a computer and continue playing from the same point they left off in the mobile version. In addition to Genshin Impact, such well-known projects as Hearthstone, Outlast, Cuphead, Pokemon GO and many others have been created on Unity.

There are dozens of different engines in the gaming industry. Some are designed for a specific game, others can be used to make games of a specific genre (first-person shooters, platformers, racing), and there are universal ones, like Unity, that open up more opportunities for developers. The uniqueness of Unity lies in the combination of several factors. In addition to the fact that this engine allows you to create projects for different devices and does not limit the developer to a specific genre, it:

has almost unlimited free functionality;
does not require deep knowledge of programming languages ​​to create the first simple projects;
has a large and active community where you can find the answer to any question, because among such a large number of people, someone must have already encountered your problem.

Before creating a game, it is important to think through all these points and present the big picture, as well as find references that you can focus on, think over the pivot points of the plot and mechanics. To create a game specifically on Unity, it will also be useful to understand some of the basic terms that you will constantly have to deal with during the development process:

Asset is a ready-made component that you can use to create your own projects. It can be an interface element in the game, a texture, a character figurine, a font, or a sound. You can purchase assets or download some of them for free on the Unity Asset Store.
A GameObject is any asset that is used in a game scene. For example, the image of a coin, its very appearance is an asset, and the five coins that the character must pick up in the process of passing the level are five game objects. The character itself will also become a game object.
Components (Components) – a part of the game object responsible for its behavior during the game: movement or reaction to certain triggers.
Script (Script) is a C# code that specifies the specific conditions for the component to work.