@dave_cochran nope! This is emulation only.
@foone @dave_cochran
Unless you open a NES, cut the clock line to the 6502, fit a toggle switch and push-to-make (pulled high push to low? or vice versa). Toggle closed to boot, toggle open, hit reset, push-to-make stepping through cycles and swapping carts as necessary until you re-insert the Mario cart then toggle close to victory.
Maybe.
@foone @dave_cochran
Oops, the NES is NMOS and that complicates things. You can single step instructions with a simple circuit (ie https://www.imania.dk/samlesaet-hobbyelektronik-og-ic-er-abn-6502-single-cycle-board.htm) but single clock cycles are "harder".