Bonk's Adventure (NES)

Bonk's Adventure is a platform game by Hudson Soft/Red, starring a double-jumping pain in the ass deformed midget caveman.

Hidden menu
To enable a level select/sound test, press and hold Down, Left, A, B, Select, Start while the title logo scrolls onto the screen. Select switches between level select and sound test mode, Left and Right change levels, Up starts the selected level, A and B change the sound number, and Start plays the selected sound.