[lsy]

Impressive that this was done in 3 days at all, but to anyone who is familiar at all with System 7's appearance, the screenshot is almost comically "off" and gives away that this is not a straight port so much as some kind of clean-room reimplementation. The attached paper is more reserved, calling this a "bootable prototype".

[wmil]

It's likely that they didn't have the rights to use the original fonts or icons.

[reverius42]

And yet they advertise: "Chicago Bitmap Font: Pixel-perfect rendering of the classic Mac font"

[chuckadams]

It's a bitmap font, so someone took some screenshots and used those. Typefaces can't be copyrighted.