Aaahh, another one of those levels I couldn't do has now been solved. =D I knew the method from the first version of this level wouldn't work and I thought it had something to do with the part on the left of the map, but I just couldn't figure out how to use all the builders and bashers properly. My own personal record for a level I could never do is about 7 years on the first level of Mayhem for the Genesis. Back when I was 12 (19 now) I could never do the first level of Mayhem, though I was just a kid. I then didn't play Lemmings again until earlier this year, so it wasn't a solid 7 years, it was still satisfying to work out on my own though especially as there were no walkthroughs for it seemingly. I was about to post on another forum for help, I had images and everything ready and while previewing to make sure there weren't any mistakes, I spotted a potential solution, turned out it worked. Don't know if it's the only solution, but it was a good feeling. XD
2 levels I'm stuck on now are Fix the road, quick! (Present 9) and Train your body (Sunsoft 4) on the Genesis version. Fix the road Quick seems to be a case of using some of the bridges to delay the other Lemmings so the ones in front have time to finish building and Sunsoft 4 I think you need to go under the wall rather than over it, haven't tried too intensively but I haven't come up with a solution either. =/