I completely forgot to post here regarding my Steel Empire clears, but I have cleared the Sega Genesis version several times on Normal.
Here's my first clear, using what was outlined as the optimal craft selection for each stage, which is the plane on all but 3 & 5:
Here's my all-dirigible clear:
Here's my all-plane clear, which was my highest score on Normal:
And my sub-optimal craft selection clear, i.e. dirigible on all but 3 & 5:
I need to go back now, and try to get a clear on Hard difficulty. I also cleared the game last night on the Steam version, again, using optimal craft selection, and got the 1CC on my first try:
I'm going to try and do the same things for the Steam version, in terms of all-plane, all-dirigible, sub-optimal selection, etc. and then try on a higher difficulty. The Steam version is significantly easier than the original, so I'm hoping to get those clears quickly, and then move on to a higher difficulty.