Instructions
Go right once you make it to Level 7.8, the last of two actual levels before this level's boss battle. Go past the Piranha Plant and the two Fire Traps until you make it to the gap. Jump the gap just as the Plants dive into the tubes. Jump up and hit the left "?" block to get the Invincible reward.
Go up the next Up tube. Your Invincibility will kill off the waiting Nipper. Continue to the next screen and deal with the Ptooie and two Plants while you're still powered up. Jump and hit the next block to gain the 1-Up reward.
Go down the left pipe and time your next jumps to avoid both the emerging Plants and the launching fireballs. Leap quickly across the bridge ahead of you, deal with the two Ptooies and jump the final two Nippers and fire-breathing Plant. Hit the resulting Slot Box to finish. Grab the Power-Up from the block immediately in the next section (7.9).
Hit the Para-Gumba here while you dodge his attack. Continue onward to jump the wooden blocks to avoid the Gumba duo. Walk forward and take the downward path at the fork. Collect all the goodies. Backtrack and take the up path. Go right and go down through the ice blocks to collect the Power-Up and the Slot Box.