Head to the middle platform under the Space Invader at the top. Make a stand here and try and get 3-4 bubbled enemies at once. Keep in mind that enemies do not stay bubbled for long on this level. Once you pop enemies in the center, clean up like usual.
The safest place to stand is the nose of the face, and simply blow bubbles at the monsters as they go past. Bubbles float up from the bottom of the screen, to the left and right of the nose, then down the columns, where the monsters first start off, as per the picture. The trapped monsters will float down to their starting locations. Water bubbles will float up from the bottom of the screen and move to the starting point of the monsters also. To avoid becoming trapped in the columns, wait until a water bubble appears on either side before leaping into the side bar to pop any bubbled monsters floating therein. The water will pull you through the small gap. If you get trapped, you can 'climb' out but this takes a lot of practice to time right.
Bubbles arrive from the bottom, and float to the top of the screen. The enemy remains in the central heart; the easiest way to get them is ride a bubble into the heart and defeat the enemies therem. Alternative attacks involve popping water bubbles before they pass through the top of the heart to trap monsters on the water stream that suddenly appears.
Note: If extend bubbles leave through the top, they're gone forever. Pop them as soon as possible for their bonus.
Move to the lower-left platform, face left and kill the ghost as he comes down. Go over to the right platform and trap the second ghost, then stand there and trap as many of the purple things as will fly down to the bottom. Then go fall down the left hole, and when you come through the top land on the structure and move to the right. From there, trap the rest of the flying purple things. Then jump down and pop them all.
You may want to avoid entering the lower holes when the map starts - the
Jump quickly to the second level and remove the three monsters there. This is easer if played with two players since the players can move the bobbled enemies to each other and pop the bobbles when meeting. Then a bobble jump is needed to get to the next level. Preferable on the left side since there should be no monsters. The monsters on the top floor can be put into bubbles without any danger by jumping close to the wall in a way that the jumping dragon does not touch the monsters but the bubbles will appear and catch the monsters.
When you enter this screen, you will see two large Bubble Busters flying past with captives.
Be careful not to fall into the small paths - if you slip into one of them, there is no way out.
Lightning bubbles will appear and float up half-way from the left or right, before going through the vertical barriers to the center. Jump into them and face away from the direction you want to shoot them.
The easiest strategy here is to wait at the start and pick off enemies one by one until the left loop is clear. Fall down onto one of the tops of the pits and position yourself on the left side of the middle pit. Blow bubbles to try and grab enemies and let them work their way into the center pit. This is greatly facilitated by long range bubbles. Once all three have floated into the center, attempt to cycle them so you can jump into the pit to get all 3 at once. As you fall, spam bubbles so you can hopefully catch the one that breaks free. This is not an easy level and the biggest stumbling block to the first treasure room.
If you are playing 2 player, do NOT fall down to get to the top until the middle enemy is the last one left.
Wait on the water bubbles to appear and let yourself be taken to the upper part of this level. If you haven't lost any life, you'll get the symbol for the Secret zone (in the upper left part of the screen).