How can you tell if your copy of a game is good or bad? The No-Intro project can answer that, and here's how it works.
Every game has a digital fingerprint called a "hash" and when two files have the same hash you know they're exactly the same. The No-Intro project records the hashes of many videogames, so just compare your game's hash to the one in No-Intro and if they match, you have a good copy!
To guarantee the best games, each NES game at Vimm's Lair is scanned nightly with the latest No-Intro data. Why nightly? Well, No-Intro isn't perfect and mistakes can happen, so over time corrections are made and the hash changes. Those changes are flagged for review, so if you see a flagged game and know where to find the latest copy please lend a hand by posting it on the Message Board.