Jetpack usage :
- egg hunts with painsaw. How else am I gonna kill the eggs on ceiling?
- better maneuvrability : allows you to go through certains passages that you can't without or to go faster from point A to point B in some maps
- anti basilisk grab as was said. I just turn on the jetpack and press space to go up while at the same time turning to face the basilisk and shot it
- get out of trapper bonus card. Doesn't work as well as basilisk since the trapper effects lasts for the full time duration, but at least it allows you to quickly move out of the place you got stuck. Which often is in the middle of a few acid tubes so it is a good thing

- building things in hard/impossible to reach places