I was writting a huge response about how I imagined the whole track when I suddenly thought it might be better to just update this project description ^^' But concerning the key change, I don't really like the one in the middle of the song, but he was necessary for the loop, because of the other keys changes in the climax. Thank you for your kind reply !
PS : I did the update on a devlog, and then on the description project, but it won't appear. Maybe that's because I'm not updating the jam entry. But I'm not sure if I'm allowed to do that, so..