This is such a great question! You know what, I grew up with the same curiosity of wanting to know how video games are made.
Making Video Games is a process that involves Arts & Science. It’s like making movies, with the exception that the audience cannot interact with the movie but with a video game they can :)
Needless to say that it requires a careful amount of Planning and Engineering.
Making a Video game requires a consolidation of several different disciplines. I will help summarize these as bullet points
- Story Boarding - This is where the entire video game story and its narration style is conceptualized and visualized. Several factors such as Character, Story, Design, Visual, elements are sketched out. Think of this stage as drawing out a Comic book showing multiple screens of action. This is the basic foundation and much like a movie, a game must have a strong plot.
- Game Design, Visual Aspects, Modeling, Graphics - This is probably the most fun aspect of the gaming development as it involves art work such as character development, environments. Based on the game’s requirement, 3D vs 2D, game Genre (Strategy, First Person, Third person) different softwares come into play for helping build out all the visual elements involved. Several 3D software are used for developing game design such as Maya, Houdini, Cinema 4D, AutoDesk 3ds Max, ZBrush are used.
- Game Sound Engineering - This encompasses all aspects related to the characters voice, object and environment interaction, background music. Depending on the games budget, each of these require a careful amount of attention and detail.
- Game Development, Software Programming - This aspect requires programming skills that help make the game come alive. It requires writing a lot of code that helps combine the visual and sound elements to make the game interactive. While it may seem difficult and scary at first, over time game developers build strong expertise and find this is a very rewarding and satisfying part of game development. Several game development software are also available to make this a relatively easy process and helps avoiding writing code from scratch. Software such as Unreal Engine, RPG Maker, Game Maker, Quest etc…). Knowledge of several programming knowledge is required such as Java, C++, Python etc…
- Game Testing - In order to ensure the games developed are bug free and ready for launch, testing plays an important role. Game makers deploy internal resources to test the product quality during development. They also give the games to external gamers to play and get feedback prior to launch. This is known as Beta testing. Sounds fun doesn’t it. And yes they are paid to play a game :)
All these above disciplines help make a game come alive.
Here's another source you can refer to
Hope this helps you get some high level understanding of how games are made.