G27: Flip to the right.
Q1: I'm not too bothered about this one, so leave as is.
Q6: Leave this one right facing. Like Q8 The lemming actually lands on the top part of the pipe first. Making this one left-facing would ignore the required holding area.
Q21: Leave unflipped. Lems can bomb twice into the steel to create a holding area.
Q22: Currently left facing, but I think because of the level's name "The Far Side" this was intended to be right facing. I know it doesn't technically add anything to the solution, but making it right facing brings the humiliation of the lemmings being so close to the exit if it weren't for that steel wall.
Q23: Leave both trapdoors unflipped.
Q24: Keep this one left facing. There's no challenge to turning round the lemmings here.
Q9, Z6, L8 and L17: Leave unflipped.
Z20: Flip both to the left.
M18: Disagree with this one (i.e. keep to the right). My fastest time solution involves the right side building upwards to the crowded pit where the left lemmings share. While executing is pretty much the same difficulty, it's quicker and easier to manage if the right entrance is facing right.
M24: I looked up the lemmings encyclopedia to find the actual intended solution, and at least it works left facing. Also, as the lems are facing closer to the wall, the journey between the two starting points is shorter, so players can choose to either climb this wall or go to the other one; so I'd leave as it is. The level is still a bit faulty in its current state, but has otherwise been unchanged apart from the left-facing entrance.