In our game, we wanted the player to feel lost and isolated (and also we had no musician...), so we didn't put real music on background. Instead of that we used an ingame noise generator to add some sound effects. As the players goes to higher levels, the pitch of the sounds goes up too, to amplify the feeling on unease
You can see the result here: https://weslito.itch.io/void (only in the downladable version)