The safest and most reliable place to find these old games is the Internet Archive.

The 2015 builds (typically from March to August) are incredibly primitive. Don’t expect rivals, Osana, or any of the complex elimination methods. Here’s what’s present:

Animations in 2015 were incredibly stiff. Ayano’s running animation was more of a floating glide. The "laughing" animation (to lure students) looked unnatural, and the murder animation was a single, repetitive "stab" that didn't sync with the character models properly.