I dunno if this is the right place to post this but given that the title of this thread has "Suggestions" in it perhaps this is the right place?
Was a Gravity Gimmick suggested before? I don't mean the "Anti-Gravity/No Gravity?" that's currently in NeoLemmix but I mean "flipping" the gravity to either be walking upside down or on the sides, etc. Something like this...
I color-coded them in the image to hopefully make it a bit easier to tell them apart. Blue is upside down, Yellow is on the right side, Green is normal, Red is on the left side and finally Purple is walking around the terrain without falling.
Now perhaps it may not be a gimmick maybe skills that allow lemmings to flip gravity in whichever direction or to act something like the Mango Boots in Lemmings 2: The tribes. There could also be an object that changes the Lemming's gravity.
Skill names since this suggests two I guess can be called... names can be changed if they don't fit.
Gravity Field/Change - Changes a lemming's gravity pull. An arrow will appear which will point to wherever the cursor is at much like how the Turner Skill in 3D Lemmings did. The skill is applied upon clicking a second time anywhere. Can cancel it by selecting another skill if you change your mind. Can also force a lemming with Gravity Boots to come off the terrain and go stick to different terrain. Think of it as moving from planet to planet.
Gravity Boots - Works like the Mango Boots in Lemmings 2: The Tribes however you can assign skills without losing the effect. Can't assign Climbers if a lemming has this skill since it'll always stick to the terrain however you can give it a Floater/Glider if you force-change gravity with the Gravity Field/Change and they will use them until they land on terrain.
This is perhaps more of an idea than a suggestion now looking at it but looking at all the gimmicks and new skills I figure I can give it a shot. It... wouldn't hurt, right?