A good background beat
The music for these games is all about repetition to give a sense of continuity. While the music can vary depending on the style or theme of the game, one thing that is evident is that the music has no crescendo or peak to it, like your typical songs do, and there is a reason behind this that is psychological. The music has no obvious start once the game is launched; it just simply starts playing without the use of an intro, so that the gamer is immediately playing. And since the music is repetitive and constant, the player is quickly drawn in and immersed in the game. As the player continues the game the repetition of the music makes it consistent and familiar, and here is where the real trick of music emerges. With no crescendo or peak, the constancy of the game gives a certain continuity that invites the player to continue on regardless of whether they are winning or losing. This lack of care for the outcome is the intention of the music, which is to make the game inviting and fun, and feel as though there is no need for an end to it as it becomes more about the full-bodied thrill of playing. The musical composition itself is so simplistic that it could be formulated on any electronic music generator that will pump out the right theme into a seemingly endless loop that will not suggest a start or end.
Music and the subconscious
Music is a powerful tool, that when used correctly, can have a large impact as it hits the subconscious and engages emotions with something that requires no complex speech or visual image. Instead it sneaks in through sound, so that while the conscious mind is focused on a single task, the music is influencing how that single task is acted out and experienced. Casino games always use an upbeat and perky song that is meant to give a feeling of fun and excitement, and to build that edge-of-your-seat feeling that will not let go. The music goes on through its endless loop and makes playing an experience on its own, regardless of the outcome.