The Cutting Room Floor collects hidden messages in videogames, but it's Cabel Sasser who most eloquently recalls them. Here's some developer trash-talk, from the Amiga age's pirate-infested waters:
I’ll warn you now that this game has a LOT of protection, so it will be a few late nights for you lot. It’s a mugs game anyway, you should be writing games and making loads of money like me (you too could afford a 16V Astra GTE). [...] In the meantime I’ll be thinking of you when I’m in Florida, spending some of my dosh.
Message in a Binary Bottle [Cabel.me]