I know it sounds stupid already but hear me out. I was watching a bunch of Halo "secret message" videos on youtube when I got the bright idea, "Why NOT have secret messages or images in Reach?" That kinda stuff is always really cool and creepy at the same time. My idea's were:
1) Have secret messages in all trailers (very well hidden) that lead to things that have to do with the game.
2) Have references to Marathon and Halo 1, 2 and 3 in it.
3) Have secret pictures in multiplayer levels and pictures/messages in campaign. Such as the face of Sergeant Johnson in a rock.
To top it all off, Bungie should pull another "Recon" on us. Give us a character, weapon or armor that can only be unlocked by the best of the best. What does this have to do with secret messages? Well, I was thinking that Bungie could create seven (their favorite number)unbelievably hard messages that lead to it. Each message will have to be interpreted into another meaning. When all the meaning are put together. You give Bungie a screen shot of all 7 and then a description of what it is and what it means. If done correctly, Bungie will give you credit for part 1. Part 2 would be get all achievements. (C'mon, you think Bungie would just give it? :p)
Small ideas but just somethings to keep people interested. Like the vidmasters did. People heard there was a way to get Recon and Halo exploded in popularity. Same here.
[Edited on 10.03.2009 5:05 PM PDT]