Haha, yeah that's a hard one, maybe the hardest in the whole series. The main reason is it has a totally different type of gameplay, where you have to actually race against the level. That time limit puts a lot of pressure on the player and a lot of people wind up making mistakes because of that. It also puts way more emphasis on movement, rather than shooting enemies (the level has hardly any enemies, relatively speaking).

Balancing it was really weird too because some testers didn't have as much of a problem with it, while others had a ton of trouble (even if the rest of the episode didn't cause too much difficulty). Again I think it's because it requires a different type of skill than the other levels. People who are good at test levels will probably find this level to be easier.

For the first tower, all I can really suggest is don't go TOO fast. If the water catches you, you'll have a chance to swim up with it or past it. For the second tower, there's no real issue with falling behind, since near the end you'll be able to catch up to it. As for the rest of the level, just run as fast as you can and try not to get hit by anything... and use pepper spray.

Maybe it's a bit too... evil of me to throw in something so different from everything else, but I'm one of those weird people who plays old platformers and finds that one really evil level (and they all have one of those) to be the most fun.