I just noticed something that I hadn't realised during testing of SuperLemmix 2.6 - because the release candidate didn't come with all the styles, there was one L2 Space level I had created earlier which I couldn't open in the RC version yet.
This level involved a Shimmier climbing up from a Laserer tunnel, using the new behaviour where Shimmiers can turn and climb up corners.
What I didn't expect was that a sloped ceiling, like the 45° angle created by the Laserer, obviously only has one pixel at the top, so the lemming doesn't transition into a Climber there - and hence, also doesn't turn around, but falls off the sloped ceiling once it ends, just like Shimmiers used to do when reaching a straight edge of a ceiling, too.
A Shimmier will only transition into a Climber (and turn around in the process) if, at the end of the shimmy-able celing, there is a straight wall above it of at least two pixels.Diagonal Shimmier-friendly ceilings only have a single pixel at the top, and hence, a shimmying Climber will not turn around here, but simply fall off the ceiling and continue facing the same direction.
In sum, I'd say this is a good thing, as on this particular level, it required me to use another skill to create a second pixel there, in order to make the Shimmier climb and turn around.
The level became more challenging as a result, which is welcome, since it's supposed to go on the final rank of whatever pack eventually emerges from this.
I just wanted to remind everyone of this behaviour, and check whether it might be a bug, so that, if that's the case, I don't make more levels relying on this 1-pixel difference. Don't worry, I'm not actually creating pixel-precise solutions here - rather, the difference of one pixel in terrain makes a conceptual difference here: It defines whether you need to use another skill to make the Shimmier climb and turn, or whether the terrain by itself will already cause him to climb and turn.
Personally, I think it makes sense that a Shimmier needs at least two pixels in height above him (i.e., the smallest vertical wall possible, since a single pixel is not a wall yet) in order to transition into a Climber. Now, in hindsight, I think I even recall WillLem having mentioned this requirement when he first introduced this skill-mechanical change.