Cool World (NES)
Cool World is based rather loosely on the 1992 movie directed by Ralph Bakshi.
This game shares the same music driver library that many other NES Ocean Software games used. As a result, there is a hidden version and copyright string:
MUSIC DRIVER V1.0 (C)JONATHAN DUNN & OCEAN SOFTWARE
Press A, B, B, A, Left, Right, Left, Right at the title screen, and a triangle will appear at the left upper screen corner of the screen, if done right. Now, you can play the "Ocean Plaza" level, which is otherwise unlocked only after all the pieces of the map have been reassembled.