Man, this game slays! The first and most obvious thing to point out is how well the different filters (transparent PNGs?) work. The illusion of a curved-screen CRT and film grain really amp up the atmosphere, especially with the strange TV character that gives you hints.
Speaking more on the graphics, they're kind of all over the place. Some of the textures (shown by the TV, mirror in bathroom, plant) look really high fidelity, whereas others (most of the exploration) have the trademark angular Flash game "feel" to them. The jarring switch between art styles sometimes feeds into the surrealist theme, but at other points feels like a discrepancy in quality. For example, the clock room looks gorgeous and simply feels like a different style, whereas the ladders you traverse really are TOO simplistic.
The puzzles themselves are actually substantive - the first one is fairly simple, whereas the next few (including exploring the different rooms) gets trickier. There are only two issues I have with the puzzles themselves. First, the piano puzzle requires you to tap some pretty small surfaces. On desktop this is fine but on mobile, players are going to struggle to hit the exact notes. Second (and also dealing with the piano puzzle) is that there are so many keys it can be hard to track which one is correct, especially with the 3rd note which is a lot harder since several of the keys make a similar sound and you really have to pay attention to the interval it makes with the 1st note to get it right. It's nothing too terrible, but I do think it might have improved user experience a bit to take away some of the keys on the keyboard, both to make the puzzle simpler as well as to make the keys easier to tap on a phone.
A separate thing I'd note about user experience is that some of the animations and game loops you get stuck in really feel like they take too long. Accidentally clicking on the TV guy and watching the hint animation, or accidentally clicking on the door loops can be really tedious. At the very least, a skip button for the hint animation would be nice.
The only other thing I want to mention is that I was waiting for all of this to mean something. Obviously this isn't the most fair question to ask, as many other games of this ilk don't explain anything at all, but the environment of this game is so different and memorable that it's hard not to want to explore this world further or get some kind of answers.