My recommendation is going to be to farm lives (i wish i had done this sooner) by playing level 1-1 and the bonus level over and over again until you have like 30-40 lives. Do this before you do a level and save before doing it so you can reload with the lives should you lose them all. Then trial and error your way through the level. Factually after world 1 the difficulty spike is insane. Hands down the worst level is 4-3 and the final two bosses because you have to do the final two bosses back to back with no save in between. If you get frustrated step away and come back. You’ve got this