During the TGS 25th Anniversary stage event, some new details on Metal Gear Solid Ground Zeroes were revealed.
The player won’t notice loading screens while playing, since they are always in the background. Only when Snake travels to another location by helicopter is a loading time inserted. The helicopter can take players from one open world level to the next.
The base shown in the demo was a relatively small world compared to other ones, as it is from the prologue stage of the game. But there will be bigger worlds for Snake to visit. As already confirmed earlier, the game will know day and night cycles, that will gradually change and affect the world of the game.