One of the most peculiar landmarks in Sand Canyon is a giant black pyramid. This mysterious structure is obviously artificial, but its origins are unknown. The walls seem to pulsate, and the many rooms within the pyramid can confound any explorer. Professor Hector from Gyromite and Stack-Up was researching the pyramid when his assistant, the Robotic Operating Buddy, broke down. You must find the scattered pieces of R.O.B. within the treacherous traps and the branching paths of the pyramid to get Professor Hector's Heart Star, one of the most difficult and tedious to obtain in the game.
Boarding the pyramid
The starting section is pretty mundane, with its main feature being its huge stretches of sand. Because of this, you should stay in the air often so that the sand doesn't slow you down. Above most of the sand pits are platforms that let you avoid walking on the sand, so make use of them as much as you can. The enemies here are pretty standard, with Cappies, Sparkies and Doka roaming about on the ground while Pterans fly in the air. The last stretch of sand you come across will carry you to the door, and running on it actually let's you get there faster. There are still plenty of enemies you need to watch out for, so don't be too hasty. Following this starting section is a short area where you go from the desert on to a mysterious black structure. Go through the door to enter the next section.
The pyramid hub
At the entrance of the pyramid, you have to jump over some gaps while steel balls frequently fall from above. Ideally, you should cross the pits with one jump, as hovering across takes too much time and will result in you taking damage from a falling ball. After going through the door at the end of the series of pits, you enter a hub of sorts. This room is filled with water, with a green blob in the center. You can choose the direction this green blob launches you in, which will let you blast through the barriers blocking the eight doors in this area. Most of these doors lead to areas of interest, especially for getting the Heart Star in this stage. If you aren't interested in obtaining the Heart Star, simply proceed through the right door. Otherwise, be sure to break the barriers of every door, and prepare for one of the most tedious methods of obtaining the Heart Star you have experienced yet.
Heart Star: Assemble a robot buddy
First and foremost, the bottom door will be the most helpful door for you, as it leads to a room containing every copy ability available. Simply swallow the Bukiset that gives you the ability you want. At the bottom of the ability hub is a door that leads to a smaller hub room with two more doors and two Health Drinks. The room behind the bottom-left door contains Coo, Kine and Rick, while the room behind the bottom-right door contains Chuchu, Nago and Pitch. In these series of rooms, you can pick your copy ability and Animal Friend for the specific tasks you will need to solve to get your Heart Star.
For the lower right room, you need Kine and the Parasol ability. In this room, there is a big gap that seems impossible to cross with Kine's single jump. However, with the Parasol ability, you can actually slow your fall and float to the other side. Just jump and use the ability while holding right. Go through the door at the right to reach the chamber with a part you need to collect. There are five parts in total, and you need to collect them all to reassemble a R.O.B., an actual peripheral for the NES. Swim against the strong current with Kine so that you can obtain the robot's right arm.
For the lower left room, you need to have both Coo and the Stone ability. In the room there is a one block gap that prevents you from passing through with Coo. There is another gap that can be created by breaking two blocks with the Stone ability, which lets you take Coo across the middle wall, but it is located just above a bottomless pit. You need to use the Stone ability on both sides, temporarily ditching Coo for the left side, to clear away the star blocks and open up the larger hole in the middle wall. You must stop falling in stone form at just the right time so you don't fall into the pit. Go through the door on the other side to reach a chamber where a strong wind blows. Use Kine to fly against the wind, letting you reach and collect R.O.B.'s left arm at the bottom left side of the room.
For the upper left room, you must have both Kine and the Spark ability. The door leads to a series of dark rooms containing three doors that look nearly identical to each other. You need to use the light generated by the Kine and Spark combination to illuminate the room, which will make symbols appear on the doors. Avoid the doors with the X symbol and go through the door with the O symbol. Keep doing this and eventually you will reach the chamber with the part you need to collect, the robot's base.
For the top room, you simply have to continue climbing a straightforward series of platforms while the screen automatically scrolls upward. Go through the door at the top to reach the roof of the pyramid. Collect R.O.B.'s head at the very tip. While making your way to the part is simple, the return trip is a different story. The screen auto-scrolls downward, and you can only fall through the blue sections of the platforms. The scrolling speed is quite slow, so you have a plenty of time to figure out where to fall through.
For the upper right door, there are a series of rooms with three doors. Each of the rooms also contain two Bukisets. Both of the Bukisets grant abilities that are required to break through the left and right door in each room, so you must obtain the abilities they grant and use them to access either door. Keep doing the same thing and always avoid the middle door. Eventually you will come across R.O.B.'s torso. Collect it to reassemble the Robotic Operating Buddy, completing the challenge for this level's Heart Star!
Out of the pyramid
Whether you just want through the arduous process of getting the Heart Star or not, go through the right door in the hub room to exit the pyramid. You still have to contend with one final hallway filled with traps. First, you must pass through three Peloo, creatures that droop down their long tongues to attack you from above. Then, you must avoid getting crushed by a series of dropping iron balls. Finally, you must evade three rising and falling stone blocks before reaching the door that lets you exit the pyramid.
Even though you are out of the pyramid, there is still some more obstacles in your way before you can end the level. Several Shotzos are positioned along the final stretch of the stage, firing cannonballs at you from varying angles and elevations. Either analyze the situation and carefully evade the cannonballs through strategic positioning or timing, or just rush through the stage, deftly dodging any cannonball that comes flying at you, until you reach the goal door.