Many of the body pieces are quite repetitive, but when it comes to the arms and hands be sure to take your time and be very careful. These parts, along with the fins, are what constitute the difficulty. Other than that, all of the pieces of the body are numbered, so just match them up as you go and it is fairly straight forward. Also note that the fins are designated to the body piece by the numbers on the end of each body section. When attaching each fin, check that the curve of it lines up with the curve on the body. Each one goes to a specific place on the tube (Inside of the curve, outside). It is also suggested to leave one end of each body section open until all fins are attached, so that you can apply pressure from the inside.