if you do the roll then jump and while your jumping press x to throw a bomb you will jump higher. its better to press x immediately after pressing b as the quicker you will press it the higher you go. using this ive found a way to skip the entire underground section and some parts after it in the level "Ole!" ive also found a wall clip with this to skip a small section in "Spelunking" but i will show you the ole skip as it saves alot of time