Glad you came forward and felt comfortable posting this in here. I'm 100% going to give it a listen. Just had a quick search on Spotify and I can't find the album, but there is a 6 hour playlist I'll try the album on YouTube first. Is it an anime soundtrack or a video game soundtrack? Either way, I'm down. I'll report back at some point in the next 24 hours!
You're mostly right about it being a video game soundtrack; most of the songs were commissioned for the game that this is a soundtrack of (Hatsune Miku: Project DIVA), but I think there's a couple songs that were made prior to the game being developed. For sake of simplicity, though, I would refer to it as a video game soundtrack.
As for the album itself, it's only 10 songs (there's 13, but the last three are alternate versions of songs already played on the main album) and it's only 34 minutes total (excluding the bonus tracks). I have a playlist of the album on YouTube, which I can link if I'm allowed to do that.