To play a 400-in-1 NES ROM, you'll need an NES emulator. An NES emulator is software that mimics the functionality of the original NES console, allowing you to play NES games on your computer or mobile device. Some popular NES emulators include:
Dumping the ROM on a 400-in-1 console and flashing it. - nesdev.org
Unlike earlier, lower-quality multicarts that had dozens of repeat titles, most 400-in-1 collections have a high percentage of unique games. 400-in-1 Nes Rom Download
The quintessential Nintendo experience. Adventure Island: A challenging tropical platformer.
The quintessential side-scrolling beat 'em up. To play a 400-in-1 NES ROM, you'll need an NES emulator
One of the earliest foundational fighting games. How to Download and Play the 400-in-1 NES ROM Safely
Re-download the file from a verified digital preservation archive. Emulator frame rate is unmapped or unlocked. Enable V-Sync or cap the frame rate at 60 FPS in settings. Controls Unresponsive Controller configuration lost on game switch. - nesdev
This process is similar across most emulators. Typically, you can simply drag and drop the ROM file onto the emulator’s window. Alternatively, use the menu bar: