3rr0r is an upcoming 2.1 mega-collaboration level by xClubstep. The difficulty that the level is to be is unknown, but supposed to be Insane 9* or Demon 10*. Only one part is complete, however (xClubstep's).
xClubstep: The level starts off in slow speed, with the player jumping over a spike while avoiding spikes from overhead. Next, they must jump into a two-block high space, only to jump out over more spikes. Another spike follows, before a challenging version of a spike with a gravity orb hidden next to it. What seems like a three-block jump with slow speed, which is impossible, moves underground next and is replaced by a normal spike. Jumps of double spikes follow, with the word "xClubstep" above. The player then must go up a slope onto a platform which moves up immediately to make the player hit a black orb, then hit a black pad to go over some thorns. A double spike follows, just before the words "Speed 1.0", which send the player into normal speed just before xClubstep's part ends.