One of the "tricks" or uses that I keep overlooking consistently is whenever the Blocker is used to just "park" a lemming somewhere - rather than to actually hold back or turn around any other lemmings. Instead, it's supposed to only delay or detain this one particular lemming.
I only recall having used this once, on a level from Lemmicks, to facilitate timing by placing a worker lemming in one very specific spot, and locking him there until something else happens.
Much like the Builder has a separate state (Shrugger), I'd coin this application as "the Stander". To me, this is a dedicated use, separate from more standard Blocker applications.
It seems even less intuitive to me than abusing a Shimmier as a Jumper (for height gain) or Walker (for skill cancellation).
Even when you do spot the potential for such an application, the challenge of freeing the Blocker again later still remains.
But I often don't even think of using the Blocker this way.
If I remember correctly, at least original Lemmings never required this.Perhaps it's a requirement on some ONML levels (I don't recall those nearly as well).
But it may be something that only became popular with the skill shadows, framestepping and rewinding features of NeoLemmix.
Nepster Lems requires this trick quite frequently, though, and that pack is available for SuperLemmini, too.
The point is that using a Blocker as a "Stander" is something you would only do if that lemming MUST be saved at a later point in time.
(Unless you're making him stand in order to run into a trap together with some other lemming later, in order to "overload" the trigger, but that's a corner case.)
In other words:
Every "Stander" must be freed at some point.And that can only be done reliably in engines with features like NeoLemmix / SuperLemmix etc.
In original Lemmings, even just timing and placing a single Miner correctly, such as on "Postcard from Lemmingland" or "No added colours or lemmings", can already be quite a challenge.
And aside from Walkers (which many custom levels don't provide), the most common way to free a Blocker probably involves a Miner.
Bashers and Diggers, meanwhile, require more setup to be used for freeing a Blocker.
It's quite surprising to me that I often overlook this
, despite being aware of other, more obscure Blocker tricks (such as cancelling a Digger with a Blocker, or turning around a Basher by making one of the lemmings walking past a Blocker, without either of them remaining a Blocker for more than 1 frame).