Just a simple map background with two rotating double helices. There's a calming soundscape with birds and other ambient noises and a subtle screen overlay to darken the edges a bit.
All resolutions should be supported as it's a map, not an image or video. The loading image may be stretched for 16:10 resolutions but the main background will be fine.
There are minor misalignments due to Hammer "fixing" things but they aren't very noticeable.