This thesis presents the process of making a simple 2.5D side-scrolling computer game and explains the used programs and their tools. The programs that I used during the game development are Autodesk Maya and Unity. Creating a game does not necessarily have to be a complicated process, it depends on how big and demanding game we want to make. Some less demanding games (for example, mobile apps) are usually developed by smaller teams, and on the other hand, larger teams work on major projects for major game publishers. Such teams have designers who create the visual part of the game, idea, story, rules, etc., and programmers who are in charge of writing codes and scripts and they should make everything work the way designers have imagined. Therefore, we cannot expect ourselves to be able to do something on the level of something that is developed by the whole team. When it comes to the 2.5D side-scrolling game, it's actually a modern version of the 2D game called the platform. In the case of 2.5D side-scrolling games, these are mostly games with three-dimensional characters and scene, but the projection of the camera is two-dimensional, i.e. has a fixed angle. This genre of gameplay was the most popular in the 1980s, and in the nineties came consoles that supported the three-dimensional gaming system and dropped the platform into oblivion. In the past few years, 2.5D side-scrolling games gained quite a big popularity, and nostalgia for older platforms is getting bigger, so old platforms are now coming back and they are compatible with today's consoles and computers.