Is there a speed run category which is just 1-1 on this site? If so can someone comment the link?

there is not besides "1-1 as fire Mario". There isn't any individual level except 8-4, as it would be a huge pain to retime thousands of 30 seconds clips and ILs in SMB1 don't have anything interesting to do besides holding right and B for 99% of them

What wolf said. 8-4 is on the leader board because 8-4 has every frame count in full game runs. It doesn't matter who can beat 1-1 faster because in a full game run framerules will stop you from saving time (not that getting a higher remainder isn't cool). The reason the only IL is 8-4 is because 8-4 IL is significant. saving a frame in 8-4 means something while in 1-1 you finish with the same time.

im p sure tecnicaly 8-4 also has a framerule to leave the level after its completion, the same way than every castle, the only reason it doesnt matter in full speedruns is because of the timing decided by the speedrunning comunity given that it is the very last level

anyhow, not advocating myself for the defense of ILs, but every level could have an IL that takes in account every frame with a correct timing (prob the way would be ending time when the flag gets up in the end of each level, or touching the axe in the other castles too)