The "normal" autosteel behaving like simple autosteel is a bug. I fixed it just now for the next release.
Simple autosteel works fine for me. Are you enabling both "Autosteel" and "Simple Autosteel"? In both NeoLemmix 1.43 and SuperLemmini, you need to do that for simple autosteel to work.
So, in my current copy of SuperLemmini (0.104a)...
This is with
Autosteel only. As you can see, Bombers are able to destroy terrain up to the edge of the steel, and the steel block remains a steel block even when partially hidden behind terrain (good behaviour):
With both
Autosteel and Simple Autosteel enabled, the behaviour is identical:
With
Simple Autosteel only enabled, steel is not steel at all:
So, there seems to be only these two options, regardless of whether you have "Simple" and "Auto" checked together, it seems that "Simple" has no function in SuperLemmini. Also, there is currently no option for "NeoLemmix Steel" (steel is only steel when visible), but this isn't necessarily a bad thing IMHO.
For clarity: what do we understand as the definitions for each type of steel?
And, how will the bug fix affect levels which currently have "Autosteel" enabled? Will they behave as in the first 2 pictures above, or will they behave like "NeoLemmix steel" (i.e. steel is only steel when visible)?
Incidentally, I made a
fully remastered version of the original games recently, which restores some missing terrain/objects and makes all steel behave "well" (as per the above examples). I'm not sure whether you'd want to use these as the official copy to distribute with SuperLemmini, but you are very welcome to do so!