I like the slanted, off-balance UI theme and style. It reminds me a lot of Jet Set Radio Future and it's oddly satisfying to look at. The hot pink, neon green, and purplish hues are also really working together well for the color palette.
I encountered some strange behavior in the guessing UI where I am able to use my keyboard to edit the contents of the guess number, but it seems like the game will still use whatever the original value is for evaluating the guess, so it seems purely cosmetic.
Finally, I was wondering about the choice of song when the vocal samples came in with "Big. Bad. Beans." until I came back here and saw that I just need to go get my ears checked. "Big. Bad. Beats." makes a lot more sense as a low-profile background track.