Don't you ever get the feeling that some of the levels on the genesis look like
The oh no more lemmings levels
Answer already mentioned, see
this part of the thread.
FWIW here's the levels that are converts:
Taxing 13 = Crazy 1
Taxing 14 = Crazy 3
Taxing 17 = Crazy 14
Taxing 24 = Crazy 6
Taxing 25 = Crazy 10
Mayhem 10 = Crazy 2
Mayhem 28 = Crazy 15
Present 11 = Crazy 5
Sunsoft 15 = Crazy 7
So it looks like 9 were converted to ONML, all are in the Crazy set, and even the Sega designers grossly underestimated how hard Crazy 10 is
Mayhem 28 = Crazy... I think 18, again not sure but it's a later Crazy level
It's 15. The remake of Crazy 5 is Present 11.
Ok, fixed post above. Thanks.
So it looks like 9 were converted to ONML, all are in the Crazy set, and even the Sega designers grossly underestimated how hard Crazy 10 is 
I don't get why everyone thinks Crazy 10 is so hard... >_>