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Japanese N64 games are NTSC format with Japanese language and can be run on Japanese N64 and Hong Kong N64s. The back of the casing has has two small slots, located just in from the left and right hand sides. The rear label states "Nintendo 64 cassette".

Hong Kong N64 games are NTSC format with English language and can be run on Japanese N64s and Hong Kong N64s. The back of the casing has has two small slots, located just in from the left and right hand sides. The rear label states "Nintendo 64 Game Pak".

American N64 games are NTSC format with English (USA) language and can be run on American N64s. The back of the casing has has two small slots, located right on the edge of the left and right hand sides. The rear label has the 3D "N" logo and indicates "Nintendo 64 Game Pak".

UK and Australian N64 games are PAL format with English language and can be run on UK and Australian N64s. The back of the casing has has two small slots, located just in from the left and right hand sides. The rear label has the 3D "N" logo and indicates "Nintendo 64 Game Pak".

Multi-Region can be achieved to a certain extent.
- Play any NTSC game on any NTSC machine. Option one it to modify the N64 cartridge slot of the NTSC machine so that it can accept any NTSC cartridge. This involves sawing the machine to make allowance for the differently placed American / Japanese-Hong Kong slot positions. Option two is to remove the back of the NTSC cartridge and replace it with the back of the NTSC cartridge that matches your NTSC machine.
- Play NTSC games on a PAL machine. You can get various adapter cartridges to allow this. Usually, codes are entered to allow the game to run via the adapter. It doesn't work for all games, and results are not always perfect. I don't know if there are equivalent adapters for running PAL games on NTSC machines; I'd be surprised if there are.