I really loved this game! Finished in 17 min with 66%. I probably could have backtracked more, but oh well. At first I wasn't sure what to, but that didn't last long. Once I got it, this game felt so clever! But maybe it would be worth it to put a rough image that subtly shows how the main mechanic works? Maybe it's not necessary, but I think it would help with that first barrier. I also think the extend/retract speed could be increased. You have to extend quite far up in some cases, and it's a bit tedious having to wait for it, especially if I mess up a jump and need to re-extend it. I was also a bit unsure how those door things that gave me new abilities worked. Sometimes it rejected me but sometimes it worked? Maybe it's dependent on your current progression, but it would be nice to clear that up. And of course, a simple music loop would really boost the experience.
Otherwise, I really love all the puzzles and how I could get creative with extension mechanic. I'm not sure if it was intentional, but it felt like I did some sort of skip by perfectly aligning the screws in the grassy area to jump up, and that felt really good. I also liked how the transition from the gray facility area to the nature-y area had a few tiles of overgrown greenery to signal the change in room, really nice!The artstyle is really nice and cohesive, and all the sound effects work perfectly for me. Really great job, and really clever take on the theme! Congrats!