Thanks for confirming the "category" of this suggestion, and for being open to the idea, namida!
Firstly - overlapping in that case is fair, as long as both objects are cleary visible and identifiable (without CPM)
I agree this should be the case in principle, but (as ericderkovits correctly identified) the main case when this causes trouble is when it comes to some type of "water" object:
- normal water areas can cover another object, especially if it's a larger one - or, if you make that other object "overwrite", like an exit, it in turn covers the water, thereby making it visually unclear that the water extends "behind" that object
- Colorful Arty's updraft areas in his Underwater tileset are "coloured" updrafts, because they are also supposed to simulate water, but water lemmings can fall through, just more slowly. Those coloured areas can also end up covering stuff or, in the reverse case, be covered by other stuff. In Underwater levels, these updrafts often need to make up the entire background of the level. That makes it possible to infer from
context that the updraft probably also extends behind other objects, but that doesn't change the fact that it's not clearly
visible.
I've used both in Lemmings World Tour. But in general, given somewhat recent discussions about the limited applications the Swimmer has in the eyes of some, I'm always interested in finding new creative purposes for under-used skills. Thus, I have a certain ambition to create new levels where navigating lemmings through water areas is an integral part of the puzzle.
Especially with the new Laser Blaster, its ability to modify terrain from a distance, and even shoot through water areas in doing so, allows to create sloped paths (including sloped ceilings) for Swimmers where there are none. This means it will also be necessary to block certain paths with traps, fire objects etc., because otherwise a Laser Blaster could easily create Swimmer backroutes.
But of course, I don't want these levels to become "accidentally unfair", just because some trigger areas (that of the water and something else) happen to overlap and then become more difficult to distinguish from each other.