About the Corrected version of Lemmings: I'm the author of it. I did take all the extracted Amiga levels, did some changes and make the game to be as similar to Amiga version. The only difference is the number of Lemmings which passes from 100 to 80, the number of builders in the level "Triple Trouble" (look under) and a few changes of misplaced one-way arrows.
As for "It's hero time!", the level is fully possible while using the "High Performance PCs" mode. This allow the game to give extra precious seconds for each levels. Didn't you read the Readme.txt included in the zip? Notice that "It's hero time!" is also fully possible using "PC Compatible" mode. In fact, I did try the "Pause the game at start to save few seconds" glitch and it works fine!
As for the differences in skills or stats of levels. I did sort them out.
Levels where there are differences between Dos and Amiga, about the skills and stats, are:
"Livin' On the Edge" (screen start position)
"Come on over to my place"
"Triple Trouble" (this is an exception for the Amiga similarity. Under Amiga, there were 10 builders for this level. Personnally, I consider that as too hard because it requires pixel precision. It IS possible with 10 builders but it's really REALLY annoying. So I did keep 12 builders of the Dos version which is much better. Just modify the level if you disagree)
"Call in the bomb squad" (screen start position)
"It's hero time!" (as said above: 30 lemmings instead of 25 and it's still possible to solve the level)
"The Crossroads" (80 Lemmings instead of less and 100% to save instead of less)
"Last one out is a rotten egg!"
"The Fast Food Kitchen" (2 minutes instead of 3)
"The Steel Mines of Kessel" (10 blockers, bombers and builders instead of 20. The level is still solvable though.)
And as for levels with objects differences (missing objects or misplaced objects): A LOT OF THEM! I did even correct a few misplaced one-way arrows like in "Last one out is a rotten egg!" at the bottom-right of the big block.
Oh, and one last thing: I did write in the txt files that I say thank you to ccexplore to changed the safe-fall distance: this is my mistake, I know you didn't change anything about it. I say thank you anyway just for the music correction.
Enjoy it!