Super Mario bros pro tip:
To continue from where you just died hold down A and press start at the start screen
I cant believe I never knew about this, so much time wasted haha.
Actually these days if I want to play some snes (Mario All Stars) I use ZSNES works great and on mac, linux, and windows. Also with ZSNES you can set a rewind key which is way more handy than the hold A and press start trick, you can just go back in “time” if you fall in that lava pit or make the wrong move.