A video game is a system of complex codes that are put into the game by a programmer and then interpreted and displayed by a personal computer or video game system. Video game systems, often called consoles, all have different hardware and require different codes to work. As a result, programmers have to program games for each console differently.
Video game developers are limited in what they are allowed to include in a video game based on the power of the console. As consoles progress in power, the freedom programmers have in developing games is expanded. Programmers are also limited by the amount of room that is available on the readable media that consoles use. This was a big problem during the era of cartridge-based systems, such as the Super Nintendo Entertainment System, and even in the early stages of disk-reading consoles, such as the first PlayStation.
The games developed for consoles always look their best at the end of the life of a console. This is due to the fact that programmers have had longer to learn how to develop video games for that specific console. Every time a new console is released, there is a learning curve that developers have to deal with in making video games for the new console.