Very fun, but difficult & controls could use work.
First, the positive. I found the game to be quite fun and the voices added to the silly nature of using explosive vents for travel. The artwork was simplistic, but considering the large maps it was good.
Unfortunately, the game is marred by very high difficulty. It wouldn't be so bad were it not for the fact that you starting adding 2 workers in the levels starting with "After You", meaning that if the player managed to somehow get the rhythm perfectly and rescue one worker, they had to do almost the exact same thing again. This just adds unnecessary difficulty and frustration to the game as the player ends up wasting more time failing after successfully rescuing the first worker than had he simply failed from the start.
The controls could use a bit of work as well. As people have mentioned, players require a certain degree of mouse speed and coordination in order to navigate through the treacherous levels. This could be easily avoided by allowing the player to map individual vents with keyboard buttons that could then be pressed when one wished to.
If you make a second game, and I hope you do, please consider these suggestions. I realize there are those who enjoy playing very difficult games, but for the rest of us, please amp down the frustration and up the fun.
Final score: 4.5(voted twice) / 9