There are quite a few backroutes at the moment, largely arising from Forestidia's replays and feedback, but some from Wafflem's streams or other sources, that I haven't had time to have a proper look at fixing yet. This topic is for me to list them so I don't forget any. Everyone is welcome to contribute replays or discussion of any levels mentioned here.
Note that the following levels have two different intended solutions, but are not "anything goes" so backroutes are still a possibility:
C - Come on Down to My Place
V - Buridan's Lix
H - Close to the Edge
The following levels have two (or more) different known solutions, but we don't know the author's intention:
C - Need a Boost?
D - Alternative Route Required
I will distinguish backroutes as "major" and "minor" according to whether they are a completely different route from the intended, or a slight variation. I don't mind leaving minor backroutes unfixed, if it would be difficult to fix them or if doing so would harm the level in aesthetic or other ways.
Known major backroutes:
C - Lix Cannon (probably unfixable)
C -
Skulls, Sludge, and SteelD - Gomen ne sunao ja nakute
D - Segmentation Fault (proposed fix by requiring 21 or 22/40)
V - Low Profile
V - Dream the Impossible Dream (level has always been backroute-ridden, might be unfixable)
V -
Dream the impossible Dream -- Proxima: Is this same backroute or new one?
H - Bipolar Maniac
DualityKnown minor backroutes:
V - Betcha Can't Save Just One! (backroutes exist in Lemmix original, probably will not fix)
V - Buridan's Lix (left solution)
H - Close to the Edge (right solution)
The following levels have recently had backroutes fixed, and need further testing:
(none)
The following levels have replays that may be backroutes, but I can't look at yet as I haven't solved the level:
H - Crown Jewel Heist