The boss starts being vulnerable right when he starts rising to prepare for the drop to the ground. If you double jump next to him and shoot him when this occurs, you can save a few seconds.
There are so many possibilities for messing around with the reverse gravity clone. I managed to complete Level 23 with 2 buzzsaws remaining by strategically using the reverse clone.
Arturo98, the reason that difference occurs is because the prices of the businesses are exponential. When you buy a business, the next business is always a certain percentage higher in cost. This "extra percent" varies from business to business, resulting in... counterintuitive results.
The game is based on an infraction system. Up to four shadowy balls at the top of the screen indicate how many "infractions"you can make until more balls are added. The three problems I have with this game are: 1) What is counted as an "infraction" seems random. 2) THe punishment (added balls) for doing these "infractions" is wildly disproportionate and game-crippling. 3) None of this is explained ingame.
Below "Health" it should show "Max Health", since once autofire reaches a high level, you will almost never get to see a potentially important statistic.