Well
The visuals are definitely the focus of the level. There are some very good-looking parts and the very beginning and some parts of the middle of the level is where the visuals shine brightest in my opinion. The ending title card auto is one of my favorite sceneries in a level period. But as a whole work, it's just so inconsistent I can't give it beyond a medium-high score. The backgrounds are very bland, and sometimes feel nonexistent. Some parts of the level use a shit ton of low visibility objects to emulate glow / low transparency blocks that tank the framerate and are barely noticeable unless you are paused or die. I often wonder how a level supposedly famous for a million objects can just feel empty in parts.
The gameplay is awkward and frustrating. I sort of get the impression you aren't actually meant to play the level based on how it is more of a tool to assist the visuals, but a lot of the gameplay just lacks the intensity to convey the highs of the song and is super uninteresting. To illustrate, much of the beginning is chaining orbs together in annoying patterns that are unintuitive and often buggy. The most fun part is the part where you spam a bunch, but not the yellow part where you spam a bunch in between inconsistent transitions and buffers I mean the orange one where you just spam as a UFO.
I can't tell if this level just hasn't aged well or if it was never that interesting because I don't think I ever cared for it when It first surfaced other than joking about how no one could run it.
Hota does fix a lot of these problems though in his sequel, "Devoreur De Dieux", which is one of my favorite levels of all time and a visual marvel. I just find this work to be a particular disappointment.

A lot of people complain that this level is just pointless object spam but I feel like you should be looking at this level keeping hota's intricate artstyle outside of GD in mind. This is essentially a series of drawings, and they're all really good drawings.