The game systems are needed to project the images of the game to the TV.  Without it, the games are worth less.  Also, there are lasers that read the game disc underside and reflects to the wires.  Then the wires transmit the images to the input holes, then to the TV screen.  We then see the screen with our eyes.

Some of the games need different systems to play on.  The games for PlayStation 2 are to be used only in that system.  PS1, or PlayStation 1, games can be played on either PlayStation 1 or PlayStation 2 because PS1 it is just an earlier version of PS2.

Then comes the Game Cube system.  The GameCube games are easy to recognize because they are so tiny.  These games are only compatible with the GameCube system.

The next system is the X-Box.  An X-Box is also a system that only plays games made specifically for it.  There is a small downside to the system in that there are a several buttons on the controller and it is very difficult to learn how to use the controller.