So, I decided to try something else. I didn't really like the alternate colors (see the floater in the previous pics), but I thought the outline didn't stand out enough. But what if I doubled the thickness of it? Well, that looked a tad messy... so then I thought, what if I do that, but make the "doubled" outline semitransparent? The result looks quite nice at all zoom levels, IMO!
Also, I added some game font text to the mockup "screenshot". Notice that unlike the other elements, it hasn't been increased in size, which allows fitting far more of it. I find it to still be very readable at 640x400, while readable with some effort (or with already having a general idea of what it might say, which is probably the case 99% of the time) even at 320x200.
(If anyone's wondering, the skill count font is one of the standard Windows ones (Calibri, I think), the game text font is the standard DOS one just without the resizing, the "blank slate" skill panels are custom made, while the icons on them are made mostly from WinLemm's high-resolution lemming sprites, apart from Bomber, Pause and Nuke (which come from the WinLemm skill panel, with minor modifications) and the Release Rate ones (made from scratch). I haven't made icons for most of the NeoLemmix skills yet, though I have for Walker, Disarmer and Cloner. The remainder, I need to make high-resolution sprites first; in particular, I'm hoping to differentiate Platformer, Stacker and Glider a bit more from Builders and Floaters than they currently are.)
I'm thinking that 1x Zoom Low-Res probably can be enabled, but perhaps with a warning message notifying the user that it might make things harder to see and that a higher zoom is recommended.
EDIT: I made the Glider sprites (though I still need to do the pulling-out-the-glider ones), and as such also made a Glider skill panel icon to go with it. But it does look very similar to Floater. Players who are familiar with them could tell them apart due to the lemmings facing different directions, while those who look closely can see the difference even if they
were facing the same way (the different shape of a glider compared to an umbrella, and if you look
really closely, you can notice the lemming is actually hanging off a bar with two hands, rather than holding onto a handle with one). Would simply differentiating them in color (which would by extension also apply to the actual lemming sprites) be enough, you think? And if so, what color would go well - I'm thinking red might be the best option (and have included a possible red version in the attached image), since blue or green wouldn't stand out as much from the lemming itself.
EDIT: Here you go. Glider!
Making it into a GIF was done with a kinda shitty online GIF generator, so the animation timing is a bit faster than it should be and the lemming jumps upwards slightly between the "pull out glider" (first 4 frames) and the "gliding" (the rest).