The Loading screen is a GUI screen here a map start or load.
There are 3 types of Loading Screens, the entire game Loading Screen, the map Loading Screen, and the teleport Loading Screen.
Game Loading Screen
This is the Loading Screen in which you see when you enter the universe that you have chosen. The intro starts with a the first 5 players in the Past Weekly Leaderboards with PlaceRebuilder. Afterwards the R2DA Logo will appear with a splash screen underneath. A loading percentage will appear but it would normally go to the menu after 1 minute.
Very little has changed with this loading screen with the exception of the changing R2DA Logo.
During Christmas, the whole sequence was dropped in favor of a whole new screen where Christmas related items come up. To go to the menu you had to press 'Continue' in the left-top hand corner.
Map Loading Screen
This Loading Screen shows the map you are about to play in the middle with a loading bar at the bottom with various 'helpful' texts. Also included is the map name, whether you can swim in the map or not and the Developer.
Various changes have been implemented from a simple screen with the map you are about to play with a loading bar.
Teleporting Loading Screen
This Loading Screen is shown whenever you are transferred to a server. It has have a light blue tint and in the middle is the word "Loading..." in large, white bubble letters.
As of now, this screen is broken and will be stuck there indefinitely. They often play the startup jingle when broken. New servers have this bug fixed, however.