Thanks for playing!
The graphics thing is totally valid. When I was drawing the sprites, I exported them at 1:1 scale because I didn't think the sprites would cause problems when scaled up. I developed this thing on a laptop, but since I didn't bother to test it on any large screens (I'm not sure why I didn't, considering I actually did have a 1920x1080 monitor nearby), I didn't notice it.
I just went and tested it on my 1920x1080 monitor. Even though it was smaller than the resolution you used, it was still noticeably pixelated.