This is a short guide for Golden Light's hidden Field Room ending. Spoilers follow, obviously.

This ending can be achieved by going to any level in the game, and digging out of the level until you reach a door. On the other side, is the Field Room.

By a wide margin, the easiest way to do this is to find the Red-Eyed memento, which grants the player laser vision, and dig to your heart's content. Don't try to dig with weapons, you'll only wear them out.

1) You have to dig quite a long way, well outside the margins of what you can see on a map. This is the reason why you shouldn't dig with weapons.

2) There are some dangers you may encounter along the way. Namely, golden clouds, fire, and mimics.

3) Digging angers the Gut. The last time I did this, the Gut's anger level started at the lowest, and, by the time I reached the door, ended at the highest. This shouldn't be too much of an issue, as it's unlikely anything will reach you in the tunnel.