Theory of Everything 2

Theory of Everything 2, often referred to as ToE 2, is the eighteenth and currently the last official level in Geometry Dash. It is also the second official Demon-rated level, preceded by Clubstep, and was released alongside Blast Processing.

Description
Theory of Everything 2's music is the sequel for the Theory of Everything theme. This level introduces Wave sequences at double speed as well as a mini Wave sequence at slow speed. It's the second level to introduce the Wave feature and the first level to introduce the mini Wave.

Secret Coin Location

 * The first secret coin is located at the first mini ship sequence. After you go through an anti-gravity portal, immediately hold then let go. You will go down then get back up to the normal-gravity portal. If you go down too low, you might hit a spike and die.
 * The second secret coin is located at the second wave sequence. After you maneuver through the diagonal hallway, try to make your wave form go down through a small entrance to get the secret coin. It is one of the hardest coins to get, as it also requires precision and control to complete the Wave after collecting the coin, as the wave is it double speed and the opening is extremely tiny for the Wave to enter.
 * The third secret coin is hidden above the course. After you exit the reversed gravity ship section (the one after the slowed cube sequence), jump on the two jump rings, even the one marked with an "X". If you do this, you will land on a platform. Then perform a jump, collect the coin, and jump again on the edge of the platform to exit safely before you enter the last UFO sequence. This sounds easy, but it is hard without practice, since the timing is critical. If you do not jump at the edge, you will land before the platform and die. Since this part is fast-paced, it is also quite difficult to jump off the edge of a platform. If you are too late, the cube will just fall off the platform without making the jump and you will also die.

Trivia

 * In Theory of Everything, all of the portals that existed when the course was released could be found in the level. However, in Theory of Everything 2, there are not any mirror and dual portals (mirror portals were last used in Electroman Adventures, and dual portals were last used in Blast Processing).
 * In the half-pipe at the end, a monster that resembles the monsters in the Update 2.0 preview can be seen with an eye (blue ring) and an open mouth to slide through.
 * The icon unlocked for completing Theory of Everything 2 also resembles the Update 2.0 monsters, and it resembles the Blast Processing icon. The only difference is that the ToE 2 icon has more "teeth".
 * Completing the level takes about 1:32. However, if you use the first UFO speed glitch (refer to errors), it will take 1:30 seconds to complete.
 * This is one of the four levels not to introduce a new game element. The others are Base After Base, Can't Let Go, and Jumper.
 * This level and Electrodynamix are the only levels to include a triple speed portal.

Errors

 * There is an error at the start of the level. If timed correctly, you can jump on the second yellow ring (which is covered by an X) and the continue to jump on the third yellow ring (without an X). But if you do this, you will crash.
 * There are a couple of design errors. If you only hit the second yellow pad and then look at the upside down wall on the left, you will notice that it appears to be broken. Also, during the slow ship segment, at about 39%, there is a design error where one of the shaded blocks is slightly pushed to the left.
 * There is an error in the first mini ship section of this level. You can skip the third gravity portal and the slow speed portal by going under them. If you skip the speed portal, however, crucial timing will be needed to pass the UFO sequence that follows. If you manage to pass it, the music will be out of sync.
 * In the final mini UFO part, it is also possible to skip the gravity portal by going under it.
 * There is a 'secret path' in the mini ship section after the second wave segment. You can skip the cube portal and remain a mini ship. At 80%, you will still be a mini ship. However, when you reach the cube, you will remain mini and die because you cannot make the first jump of that section. See this video
 * If you do not jump on the last blue ring on the slow cube, you will fall to the ceiling and crash as there is no saw blade.