Another way is that before that Koopa and Goomba, there are 2 Koopas. Draw one of those two and hit it forward so it will draw the others for you and you move behind it.

Mesen 0.9.9 is good emulator.

Also, if you want to finish the game in under 5 minutes, you should watch the gameplay videos of other record holders to find your own flaws and weaknesses.

I think just go to the settings in the emulator

Go to the video menu and change the settings

Resolution, Hz frequency and any options related to the video section

In the meantime, close the active software on Windows.

Like antivirus, internet download manager, intel managment security

Or any unnecessary software running on Windows