This seems to be a TAS (Tool assisted Speedrun) which I suppose isn't allowed here, those wall jumps are too frame perfect to be done w/o TAS so often. And it's BTW possible (and afaik done by a TAS) to not get that coin in 8-1 or for non TAS to kill a goomba instead of getting both coins
Lowest Complete Game Super Mario Bros. Score
This seems to be a TAS (Tool assisted Speedrun) which I suppose isn't allowed here, those wall jumps are too frame perfect to be done w/o TAS so often. And it's BTW possible (and afaik done by a TAS) to not get that coin in 8-1 or for non TAS to kill a goomba instead of getting both coins