Bravo! What a great mechanic, well explored. There seems to be some sort of limitation I don't understand regarding transformation (it isn't just "at least one square of new form overlaps at least one square of old form), but I was able to work around that. One careless transformation meant I had to do the final climb a second time, but the serial contorting was enjoyable enough that I didn't mind.
Thanks, glad you liked it! For reference the full rule is: at least two adjacent squares are shared between forms. Hopefully it's possible to get by just cycling through the options to pick up an intuitive sense of it.
Ah, that makes sense. I hadn't paid close enough attention to figure out that rule. The couple times it seemed I couldn't progress I realized I probably needed a different piece to progress, which encouraged me to explore further.