Silent levels

The Silent Levels (also known as the Impossible Levels) are the custom levels in-game which difficulty is far beyond the player's own skills and abilities. Despite being known as 'Silent' levels, these levels are either near-on physically impossible or humanly impossible. Near-on physically impossible levels are the type of silent levels which are only possible with cheats but can be passed in practice mode, while the humanly impossible are the ones that are extremely impossible, most of them involves around extremely tight spaces, sheer difficulty, block mazes, confusing path, and bugs.

Most Silent Levels are verified by secret ways (an example is Silent Club), while some are being verified by speed-hacking, no-clip, or using mod menus, and others are verified by simply altering the game's files. However, due to Update 2.0's speed-hack patch, it is impossible to verify an impossible level with it. Therefore, using mod menus, no-clip, or file altering are the only ways nowadays.

The only Silent levels to ever be beaten legitimately are SilentFunk (achieved by GeometryJosh on 21 September 2016 and SrGuillester ), IceClub (Achieved by Dual Kiki on 28 September 2016), and Sakupen Hell (Achieved by TrusTa on August 2016). RpgRaketti is trying to verify a Silent Club rebirth and extension known as Hushed Halls, currently with a record of 41%, while SuperexGD verified his own nerfed version on March 13, 2017. That version remains unrated for now.

Backstory
The origin of the Silent levels began in a simple 1.6 unregistered creator named as Play 1107696, who was the creator of the notorious level named Alphabet X, a Very Hard/Insane Demon which was first beaten by Zobros back in May 2015. He has also uploaded a level called Silent Club, an extremely hard and near-impossible Clubstep remake, hence the name. The level was used to be rated Demon, however, until Cyclic found a hard-to-reach secret way in the level, which caused it to be downgraded. After then, a player by the name of Sailent, aka Nautilus2k, has started his own career of making Silent levels. He has created several impossible levels including Deadly Clubstep v2, Silent Clubstep, etc. As time goes by, a few creators decided to release their own impossible levels, such as the infamous Death Corridor.

Silent levels have been popular again since Cyrillic and Sailent released a collaboration during Update 2.0 called Silent Circles, which is an impossible Nine Circles remake. This level introduced insane wave spam which is physically impossible without hacks, auto parts or Practice Mode.

Design
Silent Level designs vary depending on their creator's choice. Some were Nine Circles and/or a Hell-themed style. Some are extremely dark that it's almost impossible to see what was going on. Most older Silent levels, like Silent Club, were simply Clubstep-styled.

List of Silent Levels
''Please help contribute into this list by adding a few more levels. A more exhaustive list can be found here, the silent levels being in the categories >1.''

This is the chronological list of all the Silent Levels published. Please note that levels like Very Easy and Red World (which are both impossible due to a bug) are excluded from this list.

Trivia

 * A lot of people debate if some old levels like Silent Club are possible. Many people say it's possible, but extremely hard, however nobody has beaten them without hacking so far.
 * Cyrillic created a possible version of Silent Circles named Supernova Circles. It was rated demon, but got unrated in less than 10 minutes, because the creator was known for hacking levels.