The Dicenomicon allows you to select from a variety of backgrounds, including both textures as well as full screen images. Selecting "Background" from the Customization section allows you to pick the one you like (a small swatch from the texture/image is shown to give you a preview).

By default, different dice kinds have different colors - six sided dice are red, eight sided green, etc... You can change this to make all the dice use a given color (or use whatever the default mix of colors would be). Note that if you specify the color of dice inside a formula, it will override any setting here (which is the whole point of having color coded dice groups in the formula).

There are a wide variety of textures that can be used for rendering the dice. The different textures not only use different images, but also have different properties which determine how they are rendered. So some dice textures are shinier than others, etc... Note that all dice are draw with the same texture family, regardless of any color settings.

The "Physics" section allows you to pick from several different physics models (or even customize your own). This controls how much the dice bounce, roll, and how they react when they collide. Note that when you customize it, you may end up with settings that cause the dice to have problems "settling down" or otherwise rolling properly.

Similar to the way that you can control the physics and dice textures, you can also alter the lighting scheme used. There are several "bright" and "dim" settings to pick from, which will alter readability in some cases (and add extra atmosphere in others).

"Game Rooms" are a way to support different configurations as a set, allowing you to have a "game room" for one game, and a different one for another (including different favorite dice formulas, textures and backgrounds) - no longer do you have to scroll through favorite formulas to find the ones for the game you're currently playing. The "Game Room" section of the settings screen shows the current game room - tapping on this will allow you to select a different room, delete rooms, and make new ones. When a new game room is created, it gets all the settings from the default game room, but once you customize them, those settings will be for that game room only.