I didn't really notice the graphics all that much, though I will agree that the actual design and stuff is well-done. After the first couple hours I was more appreciative of their visual design language than any aesthetic, though there were some sections that would probably have been pretty cool to see if I'd slowed down a little.
Honestly, I think it was the gameplay I tired of first. Some of this may have just been the fact that once you beat the game there's not a whole lot of reason to go again other than just to see if you can make it, but by that point I'd gotten so polished that it was either a matter of dying stupid really early or finding my groove and making it pretty far in. The final boss fight was disappointing, though spectacular from a visuals perspective, so that kind of put an end to my goals (admittedly, it was a very clever idea, just was too easy).
I didn't really notice the sound all that much, which is probably a problem. I found it functional in the sense that I knew what was going on, but the constant ringing from all the loot lying around got on my nerves as much as it helped me. A lot of repetitive screaming, grunting, and weapon clashing doesn't do a whole lot, but I've gotten used to it as a sort of par for the course of games thing.
There's actually a minimap/map function, but it's locked behind a relatively rare item. I think I was seven or eight hours into the game when I first found it. It's kind of a Pyrrhic victory when you find it, because then you wind up going without later and it's very jarring. It also doesn't show enemies, which is kind of a big deal because unless you pull up the map entirely by pushing M it will just let you get shanked while you're trying to figure out which type of genie it's indicating.
Actually, you can leave between levels (it's kind of a hidden feature) and take a break, but you just can't during levels.