Wonder Boy in Monster Land/Round 4

Part A

 * 1) From a castle to a tropical paradise, you will find yourself on the right edge of the map.  Proceed left to the platforms over the water.  As you jump from platform to platform, you will probably reveal many hidden money bags.  You will encounter a couple of jellyfish jumping out of the water, attempting to impede your progress.  They are easily removed with one sword swing.
 * 2) When you reach the center island, you must deal with a crab.  Once you start hitting it with your sword, don't stop swinging.  You can likely defeat it before it ever has a chance to recover.  It may drop an inventory item such as a Gauntlet or Winged Boots.
 * 3) Proceed along the last few platforms, and watch out for the two leaping Jellyfish near the end of part A.  Try to get rid of at least one before you attempt to jump over to the final ledge which leads to town.  If you happen to fall into the water, you must backtrack right to the island and try again.

Part B

 * 1) Don't relax your guard upon entering Baraboro town; you are about to be introduced to the very fast moving red rats.  They will advance towards you very quickly.  Be ready to strike them down with your sword.  They don't leave money behind, but they might leave a heart if not a point item.
 * 2) If you haven't bought any armor up to this point, consider buying the Light Armor from behind door A.  If you bought the Light Armor from the previous stage, you should consider buying the Heavy Armor for 100 gold, but only if a) you still have medicine, or b) you don't have medicine, but you have over 200 gold.
 * 3) Be sure to climb up the ladder to where door D is. As long as you have a Light Shield at this point, there is little reason to spend your money on any other shield for now.  However, after removing the rat from the platform, investigate the window to the right (labeled "!" on the map) by pressing up.  If you collected the letter from the cave, you will discover a hidden door where you will exchange the letter for a flute, which you are instructed to blow on Pororo Island.
 * 4) Once you are done in town, continue left.  The next platform is spring loaded and will propel you to the island where another crab awaits.  Defeat the crab and you may get another useful item.  Then leap to the first of two floating platforms.
 * 5) * At this point, if you do not have medicine, but have over 100 gold, drop down between the two moving platforms, and you will discover a secret underwater section. Push left as you fall down to make sure that you land in front of the shop at door E.  This shop will sell medicine for 100 gold.  After you buy it, proceed right to exit.  You will meet an octopus which you must stab many times to defeat.  Strike down, or ignore, the jellyfish as you climb up the steps.  You will return to the island above.
 * 6) Jump across the water to the land on the left.  Watch out for a crab or red rat when you arrive, and approach door F.  Behind it, you will encounter the stage boss.

Boss
The Kraken is no push-over, but he is easier than he may at first appear. The Kraken hovers over head and sprays poisonous orbs into the air which fall down to the ground. He will generally occupy the right side of the room as he sways back and forth. This leads to two different strategies; a cautious one and an aggressive one. For the cautious strategy, stand left of center, just beyond the range where the Kraken flies, and jump up to strike at him every time he approaches you. Keep an eye on the orbs that fall from above, and maneuver between them as they fall. You should be able to defeat him with no damage. The aggressive strategy takes advantage of the fact that Kraken cannot harm you just after you strike him. Therefore, you can jump up and slash him, and safely pass through him while he is blinking. When you land, turn around and prepare to jump up and slash him again, passing through him upon successfully hitting him. Either way, he will drop a key and eight coins when you defeat him. Grab the coins before the key.

Once you finish, head to the gate at the left end of the stage. Another crab or rat may reappear in that time, so be prepared for one last encounter before you exit.

Arcade/PC Engine

 * Jump in front of the second palm tree in the beginning to make a coin appear.
 * Many platforms (2, 3, 4 (floating), 6, and 7) in the beginning of part A have a hidden money bag above it. For the floating platform, you must jump when it reaches the highest level to make the money bag appear.
 * The last floating platform in part A has a hidden money bag if you jump up along the right portion of the platforms path. This is difficult to collect unless you jump as the platform is moving right.
 * If you jump to the left from door D, you will reveal a hidden money bag. However, if you face right, and allow the rat to shove you off, the money bag you reveal will have over 60 gold in it.