Picross 2 (GB)
Clear saved data
Highlight a save game file, then press and hold Select + A + B. An "Erase?" message will appear; press A to clear that file.
(For Super Game Boy only.) On the title screen, hold any direction on the Control Pad and press Start. Keep holding the Control Pad until the screen border color changes. Depending on the direction held, a different color border will appear.