After finishing the Eye of the Beholder 1 game, if you have completed the 12 quests for each dungeon level, you receive a password of 4 digits at the ending writings.

Does anyone know what is this code for? How do I use it? Thanks!

I assume you are referring to Eye of the Beholder. I've never done this myself but I've heard the rumours. Not sure it was ever used for anything, possibly meant for the next game as some sort of special bonus, but I don't think anybody knows.

Here's a video of the code by the way - looks like the code for this winner was 0002
https://youtu.be/KtU9ZWTm5bA

Yes, friend. Sorry, I forgot to specify the game. Edited the first post.

there´s another video with a different password... 0752