This is a very situational run because of the excessive, EXCESSIVE amount of RNG involved. Frankenstein dudes will mess you up. In general you wanna be decisive enough to where you can figure out in the moment when it's best to damage boost to accomplish a goal or when it's best to go grab a piece of candy inside a stairs room and play it safe.

In every stage you need to collect 12 fruits and collect the key to advance. Unless specified otherwise, the key will randomly appear inside a stairs room. The stairs spawn only when you're standing on the right side of the stage except in World 3. It helps to memorize the layout of each stage and where you can or can't kick trees for fruit. If you kick a tree and get the fruit, you can't kick a fruit on any other tree on that same vertical coordinate until you kick a tree on a different vertical coordinate.

World 2: Kick the rock in the upper right to make the key appear. If it's gold or candy, pick it up first. If it's a scorpion, the key won't appear, kick the rock in the lower right instead, collecting fruit on the way. Damage boost past the bear thing for the key.

World 3: Position yourself in the middle of the tree on the bottom. Hold down B once the turtle reaches the middle of that tree on the right (timing might be different on console). Position yourself on the near-pixel-edge of the turtle, time your jump to land on land and not hit trees. Stand by the water to activate stairs World 4: One of the bad key RNG stages.

World 6: Start farming gold, because this is probably gonna take a while. I like to exhaust everything that can be done in this stage and just wait in the area that the stairs spawn World 7: Buy 2 slingshots World 8: Buy an invincibility potion (slingshots aren't actually needed in this stage) World 9: Damage boost for the key World 10: Buy a heart