The jetpack is the best thing since sliced bread, but it feels overpowered. According to the wiki I guess it used to have a flight time of like 200 seconds, but now it seems to last *forever*. It also seems odd that you can cram 30 buckets of biogas into the thing. I propose a few changes:
1) Should only hold 4 buckets of fuel
2) 4 buckets of biogas should only get you ~75 seconds flight time
3) Extractor on a bucket of biogas gets you a tiny pile of fuel dust. 9 of those gets you a fuel dust. Fluid enrich biogas on that gets you rocket fuel. Rocket fuel lasts 5x longer than biogas, giving you over 6 minutes flight time.
Then again, maybe rocket fuel should be extracted from electrolyzed water?