Starting from a fresh game of Super Mario World (SNES), what sequence of levels should be played in order to reach a lives total of 99 as quick as possible?
From my experience with the game, I know that there are a few levels that are very effective for 1-up farming, but many of them are a little far into the game, and so might not be optimal from a speed-running perspective.
There could be multiple ways to answer this question, (like in a one or two player scenario, for example), so I should clarify that what I’m looking for is for one player to have a life total of 99.
Assuming you want to get 99 lives as fast as possible from a fresh start, I believe the optimal solution is not to race to later levels but to spam Yoshi’s Island 2, where you can quickly get several extra lives by using the Koopa shell near the start. Just throw it at the line of Koopa Troopas and run after it to keep it on screen. If done correctly, you should be able to get five extra lives within 15 seconds of starting the level (probably even slightly less, but I can’t test it right now). Since you start with 4 lives, repeating this process 19 times should suffice.
You have to complete the level once, after which you can exit the level midway after gaining the lives. Assuming each attempt takes about 15 seconds, plus maybe additional 30 seconds for finishing the level for the first time, you’ll be packing 99 lives in about five minutes fifteen seconds from a fresh start.
(it is also possible to use a glitch in Yoshi’s Island 2 to inject arbitrary code in the game (video), including the possibility to add any amount of lives but since it’s both insanely difficult and likely to be considered bad sport I’ll leave it as a footnote)