The ,8 refers to the device number of the first floppy drive. Programs loaded that way would load into the BASIC workspace.
Adding ,1 to the end of that would load the file starting at the address indicated by the first bytes of the file. Many game companies would use that to load the file over the top of the command interpreter so the program would start automatically. That was an attempt to make it easier to play a game but also to deter software copying.
