Man, are pico 8 devs just auto loaded with good pixel art skills? Feels quite polished!
The flipping gravity mechanic was a little bit of an "oh" at first given how it's been done plenty before, but given the way it's used with attacking plus breaking blocks and it's quickly distinguished.
Then the block gravity switching. At first I was like "woah interesting", but the novel appeal wore off when it turned to needing to backtrack through difficult areas (spikedrop). Perhaps I'm missing something but as far as I can tell the spike drop is same both times, having instead a challenge that changes up when you switch gravity would probably alleviate the issue. Still, messing with the world is neat and something I've been looking for more games to explore so I'm glad to have found this.
After a while though the very difficult nature of the game just became a bit annoying, the precisely weaving through spikes segment (after flipping the pink box dudes) just felt difficult for the sake of being difficult, like that kind of precision timing test has been done in just about every platformer, and without any music or story or such there wasn't really much incentive to get good at it. I guess what I'm saying is if a challenge doesn't exist for the sake of conveying a new idea, what's it there for.
Then I found out I needed to do it another 2 times -_-