Iwatobi Penguin Rocky x Hopper is a party game featuring two titular rockhopper penguins. Despite only being released in Japan, it was apparently successful enough to get a sequel.
Pictured here is an enormous bitmap (4200x2800 pixels) inserted into the game as a dummy file. It contains a number of comments from the developers, as well as some renders and scribbles.
Dial-up and slower broadband connections beware!Archive