This level is believed to be entirely impossible to do without locking boulders.
Evil Variant Sokoban Level 2b
- - - - - - - - - - - - - - -
- - . > - - - - - - - - | . . . . . . . . . |
| . . . . . . . . . . | | . . . . . . . . . |
| . 0 - - - - - 0 - . | | . . . . . . . . . |
| . . | . . . | . 0 . | | . . . . < . . . . |
| . 0 . 0 . . . . 0 - - | . . . . . . . . . |
| . 0 . . 0 . . | . . | | . . . . . . . . . |
| . - - - 0 0 . - - . | | . . . . . . . . . |
| . . 0 . . . 0 . | . - - | . . . . . . . . . |
| . - - - 0 - . . 0 . ^ - - - - - - - - - - - - + |
| . . . | . . 0 - . ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ . |
| . . 0 . . . . . . - - - - - - - - - - - - - - - -
- - - - - . . | . . |
- - - - - - -
Label the Boulders
- - - - - - - - - - - - - - -
- - . > - - - - - - - - | . . . . . . . . . |
| . . . . . . . . . . | | . . . . . . . . . |
| . A - - - - - P - . | | . . . . . . . . . |
| . . | . . . | . R . | | . . . . < . . . . |
| . B . D . . . . S - - | . . . . . . . . . |
| . C . . E . . | . . | | . . . . . . . . . |
| . - - - F G . - - . | | . . . . . . . . . |
| . . H . . . K . | . - - | . . . . . . . . . |
| . - - - J - . . L . ^ - - - - - - - - - - - - + |
| . . . | . . M - . ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ . |
| . . N . . . . . . - - - - - - - - - - - - - - - -
- - - - - . . | . . |
- - - - - - -
The Problem
. . - - .
. K . | .
- . . L .
. M - . .
. . . . -
The core of the problem with this level is the region shown with the purple background above, blocked in by boulders K, L, and M. There isn't any way to get inside that region without locking boulders.
Systematically:
  1. It's obviously impossible to get inside that region without moving one of the three boulders, K, L, or M, out of the way.
  2. Boulder K cannot be moved from outside the region without locking boulders because
    • Pushing K north or west would require being inside the region already.
    • Pushing K east locks it into a corner.
    • Pushing K south, without moving M first, locks boulders K and M in place.
    • As we will see in a moment, the only direction M can be moved is north, which would altogether prevent K from being moved south at all.
  3. Boulder M cannot be moved from outside the region in order to let the player in, without locking boulders, because
    • Pushing M south would require being inside the region already.
    • Pushing M east or west is impossible due to the wall.
    • Pushing M north is possible but does not allow the player into the bounded region or otherwise help the situation.
  4. Boulder L cannot be moved from outside the region in order to let the player in, without locking boulders in place, because
    • Pushing L east would require being inside the region already.
    • Pushing L north or south is impossible due to the wall.
    • Pushing L west, assuming we could even get behind it to do that (which I'm not sure is possible either in any case) does not let us into the region unless we push it two spaces; but pushing L two spaces west, without moving M first, locks boulders L and M in place; and similarly to K, M can only be moved north, which does not help.
  5. The level does have one more boulder than pits, and furthermore one of the pits does not absolutely have to be filled to get to the up stairs, so in principle a solution that locks boulders could be possible. Given the location of boulder M, I find it highly improbable that anything that locks it into place could lead to a solution. That leaves pushing K east, but doing so requires being in the region west of it, bounded by F, G, H, and J, and I don't see a way into that region either, without locking boulders, for reasons similar to the ones discussed above. In particular, it would be possible to get in by pushing E east, F south, G east, then K east; but this effectively locks not only K but also F, J, and H.
  6. AmyBSOD claims to have found a solution that involves pushing K south, which cannot be done in nhss both because it requires moving diagonally between a boulder and a hole and also because it requires using a hole to return via the stairs from the level below. She says this:
    • First you need to arrange P and R.
    • Then C goes one to the east, A and B one to the north.
    • D east, and then K south, getting both it and M stuck.
    • After getting K and M stuck, J goes south two squares.
    • Then you squeeze between L and the pit, move S up one square and then there's some rearranging that I don't really remember; you need to make sure that moving P west doesn't block the others.
    • Somewhere in between, J will go back north one square and then N goes west one square.
    • And once you established a "loop", you can push L east one square, go back around and push it south into the pit. Obviously the "extra pit" will stay there and not get filled with this solution.
    • Eventually you will jump down a hole to push A back south, but only after making sure it won't block B.
    See also: AmyBSOD's writeup of her solution and a ttyrec (I haven't watched this yet; she says start at turn 6034.)