Full BIN/CUE sets for Saturn games take up 500–700 MB each. The CHD (Compressed Hunks of Data) format reduces Metal Slug to ~320 MB with no loss in quality.
Unlike the arcade original, the Saturn port includes a (or "Arrange Mode"). This mode adds: Metal Slug ROM -ISO- Download for Sega Saturn -...
: Since the game is a Japanese exclusive, you must use a Japanese console, a region-free modded console, or a region-patching utility for your backup. Playing from Backups (ROM/ISO) Metal Slug ROM & ISO Download for Sega