I didn't have any issues with it. I found the music to be good and the graphics perfectly fine too. I'm guessing he's going for a minimalistic look which doesn't look half-bad honestly. Game also runs fine. Unity's fairly easy to run in general anyways.
And who gives a shit what engine it's running on? There are some million-dollar games out there that run on Unity. I mean I get it has some shame because it's easily accessible to people who make a game in twenty minutes, but if you know what you're doing you can really make some Unreal Engine-quality shit. It's amazing.