Credit goes to さくらんぼう for finding this strat, you can find his vod about it here https://www.nicovideo.jp/watch/sm3606… . The idea is to keep entering and leaving the first room until you see the patter Up Right Up Right, after that re enter and go through. Normally the fireballs are very troublesome due to their random movements. With this we know where they are going to move to which makes avoiding them quite easy.
This will work if you had no issues getting through the first room. Ram Watch is up to help people attempting this to match the values during each room transition.
This will work if you had a small issue getting through the first room, you will be looking for the left fireball to be cut off by 50% when you exit the room Ram Watch is up to help people attempting this to match the values during each room transition.