File Type
The "Z64" file extension is considered a gaming file type that contains a video game ROM image. The ROM image is an exact copy of what you will find on the Nintendo 64 game cartridge. Only special Nintendo gaming emulators can open this file type.
Other Extensions
The Nintendo 64 video ROM image is sometimes saved under the "N64" or "V64" file extension. In your hunt for new game tiles you may come across one of these other extensions. If you do, know that its still compatible with your Nintendo emulator software. The data in the file maintains the same copy of the game that was exported from the Nintendo 64 gaming console.
Programs
There are a number of programs that open the "Z64," "N64" and "V64" file extensions. On Windows computers, some of the popular emulators include Project64, UltraHLE, Nemu64 and Mupen64. On Mac computers, you can choose from N64emu, Mupen64 and SixtyForce.
Sources
You will find dozens of Nintendo 64 emulator websites online that give away the games for free. One popular source for "Z64" files is Free Roms (freeroms.com), where you can download and rate popular game titles, such as "Mario Kart 64," "Zelda," "Starfox 64," "Paper Mario," "Rampage 2" and "NFL Blitz 2000."