Recently I came across an article titled: 'The 15 Most Annoying Levels In Video Game History', and right at the top of the list was the second half of the Dam Level (a.k.a the second half of Level 2) from the first Teenage Mutant Ninja Turtles game. This level seems to come up a lot when people start talking about tough levels in games, but it's really not even all that hard as long as you remember to stay away from anything that's glowing. I've prepared a video walkthrough to illustrate.
Observe:
No, the Dam is child's play compared to Level 4, the JFK Airport. That level is an exercise in annoyance and difficulty, and one that we'll have to tackle another day.