At the title screen, press Up, Down, Left, Right, Left, 2, Up to activate Hard mode. Or press Up, Down, Left, Right, Left, 2, Up, Up, 2, Up to activate Rock hard mode.
By falling off the first breakfast table on the bottom right hand corner you will gain infinite lives
Please do the following at the title screen:
While on a breakfast table, stop on a puddle of milk and press Up+1+2