it's not reimplementing it from scratch. it's developing a runtime engine that can read the original diablo 2 files. It says right in the README with big letters. You can't use this unless you have a legal copy of diablo2 and an expansion.
>You can't use this unless you have a legal copy of diablo2 and an expansion.
Or an iso acquired from a random torrent site. I've owned a few copies of D2 in my life and given blizzard years of my time, who knows where the booklets with the CD keys are. At least my copies of lod have it printed on the cover. I feel no qualms whatsoever about not giving blizzard more money for another 'legit' copy.