Perhaps you didn't not see the grabbing spot in the last rectangle? If you step on the floor all the grabs reset so you re-use it for the last step. It's actually pretty easy compared to the top left section...
Wow I played a lot of itchio games. This is one of the bests! I never writed anything in the comments before and clearly this deserve positive review... But can you open the door leading outside? or this secret is a dead end.
