This is an extremely minor cosmetic bug, but I thought I'd mention it just in case.
In the song information pane, there are two "System:" information lines. One is Audio Overload's file identifying the filetype (i.e., "Master System (.vgm)"), and the other is the VGM's own line identifying the system (i.e., "Sega Mega Drive / Genesis").
It might be good to change Audio Overload's System: line to a File type: line instead. As well, it might be helpful to identify that VGM files can be for more systems than the Master System. Alternately, the VGM's System: line might be ignored, and whatever system it identifies used as the system name in Audio Overload's own System: line.