For the most part, this PC version is a pretty faithful port of the famously difficult first TMNT game for the NES, which was also released in 1989. For some inexplicable reason, though, a single block is missing from a sewer section in Level 3, making an otherwise trivial gap impossible to clear. The oversight was fixed in time for the game’s 1990 European release, but US players were stuck unless they knew how to cheat.
This is why we have QA.
Also, I had no idea TMNT was on the NES and DOS.