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Smash the pot and grab the brown potion. Head to the right, avoiding the falling flowerpots, and throw some at the strange man, then jump on him to reach the upper level (if you kill him simply go back to the left a short distance and then return). In the next area head right, avoiding the jumping fires. The pot contains some meat if you can be bothered fetching it. Anyway, climb the vine to the next area. Here drop the potion on the lava to create temporary platforms. Use these to reach the other vine. Repeat the process in the next area. Watch out for the bat hovering by just as you jump up onto the next area. When you reach the next floor swap the mud potion for a red one (this is important!) then quickly jump onto the falling platform when it's at its highest to clear the blocks (if there is no platform walk back to the left a bit and then return). Head through the door.

In the next area the blocks contain a gold coin and a crossbones. Heading left will earn you some loot but loops back, while heading right lets you finish the level quicker.

[edit] Left

Step on the upper platform, then quickly head under the other one before it lowers. Slowly walk to the very edge, then drop straight down. If you miss you'll end up back at the start of the round! Once here jump on the horizontal platform then quickly dash under the other one. Head right and drop down and you'll find another of those item-spewing pots. Head left then right, avoiding flowerpots as before. Break the blocks and head right and you'll end up back at the area with the vines.

[edit] Right

Head right. Jump over the holes and moving platforms, then fall down the big hole and push to the left. Through the door you'll end up in an area with a pot spewing loot all over the place. Simply walk around collecting all you can. You'll see some little lightning-spewing men. They are invincible and easily avoided (when their faces light up they're about to throw lightning bolts). Eventually you'll reach a door. Go through it quickly, or the forced screen scrolling will kill you. In the next area blow the bricks and hop on the platform. When the wall on your right ends the platform will soon disappear, so jump across onto it. Once there jump as far to the right as possible. Blow the bricks and the pot and collect the key (the bottom-left block has a crossbones). Fall down and unlock the door.

By now you should have collected enough bones to access the Bonus Stage.