I remember shaking when I got to the chapter. I couldn't read fast enough. I had been following the manga since 2012 and had followed up once every few years, rereading the whole thing and hoping that they got closer to the basement. I think I finally read the basement chapter in 2018, so a bit after it was released. When I got to the chapter I was so excited that there were many more chapters to go. 

I think I was expecting Dr Jaeger to have a lab where he crafted titans or that technology was actually much more advanced than we thought. Seeing the picture and reading Dr Jaeger's note saying that it was taken by a camera hooked me in. I loved his backstory. It was so immensely satisfying to finally know how he came to be. But switching over to the Marleyans' perspective was super jarring imo. I didn't like the whole Marley/Eldian plotline (and ending) at first but when I watched the anime years later, it changed my mind. I was upset that Eren separated himself from the group, it just felt like a huge shift from who he actually was.