What is this game shown on the TV series Preacher?
This is Qbert.
Q*bert is an arcade video game developed and published by Gottlieb in 1982. It is a 2D action game with puzzle elements that uses "isometric" graphics to create a pseudo-3D effect, and serves as a precursor to the isometric platformer genre. The objective is to change the color of every cube in a pyramid by making the on-screen character hop on top of the cube while avoiding obstacles and enemies. Players use a joystick to control the character.
While I was hoping to find this might be Faster Harder More Challenging Q*bert (see: Wikipedia's article on Q*bert: Section on Faster Harder More Challenging Q*bert), my research indicates that this is from Q*bert Rebooted's classic mode (see: Wikipedia's article on Q*bert: Section on Q*bert Rebooted), based on the side artwork and some image searching. (e.g., seen in media shown at Steam's page for Q*bert Rebooted, or if you scroll down a bit on this page: Playstation Lifestyle: Q*bert PS4.)