I'll preface by saying that I've always been a tad bearish on abstract, "object collection" type levels. Not cynical like GD Twitter's early opposition that unironically mimicked Nazi condemnation of "degenerate" art, but a not insignificant doubt of such levels' ability to pull off the whole "show, don't tell" routine beyond their scattered thousands of objects and the emotions such disconnect might evoke. upstairs isn't the first to supercede them, but there's something fascinating and unique in how upstairs is so unified, like a body. Even more important than the out-of-the-box firepower upstairs' lo-fi noise provides is the unknowability of its details contrasted with the opaqueness of its wider setpieces - "Hello" is the only common word in the different languages we're speaking, but I am forced to understand the energy unceremoniously thrown at me, how upstairs obliterates itself just to chart a reasonably playable route. Not every sequence manages to vault over the devolution of structure into pure self-affirmation, but even those have some beauty in them. If you like this level, you'd probably like Selected Ambient Works Volume II.