Thanks to Godless Savage on Crossing Blades:
*Note: You will have to put the disk into your computer to get them.
DMC DVD Easter Eggs
So far, I know of four--all on the 2nd disc of the 2-disc set. I find them much easier to get to on the computer, because you can just move the mouse around until something highlights. If you are using a TV remote, you'll have to do some inventive clicking.
In the main menu screen, you can get a leaf to highlight above the menus--that plays a featurette on the catering (try left clicking twice from According to Plan). Talk about having to feed an army! And in some cases, they were doing it while the kitchen was basically flooded, LOL.
Also in the main menu screen, you can highlight a patch of grass at the bottom of the menu--that will play a featurette on the Flying Dutchman 'Twins' (try going twice left and twice down from Creating the Kraken).
Go into Mastering the Blade and highlight the keyholes in the chest (go once left and once up from Return to Bonus). That plays a featurette on the Key Dog.
Go into the Jerry Bruckheimer Photo feature, and highlight another patch of grass (try clicking left a couple of times). That will play a really fun featurette about the 'Coconut Man'.
The key symbol you see is only for the menu items....for the Easter Eggs, you won't see a key, but you will see a patch of grass or whatever that sort of highlights in yellow. That's what you want to look for. It can be subtle...like the one with the keyholes, it literally is JUST the keyholes of the chest that get a brighter yellow. Once you get that, you should be able to hit 'select' and get it to play.