/vr/ - Retro Games

Here's a excerpt from a Japanese book, translated to English as "Otaku: Japan's Database Animals". Here they refer to YU-NO as a visual novel, which means:
1. The original Japanese text called it a visual novel
2. The translator thought it appropriate to label it a visual novel
There's no way to objectively say that it's a visual novel, but this is good evidence that it's not unreasonable to call it one.