I'm absolutely terrible at rhythm games, but this game hooked me and didn't let me go until the end when they throw a 240 bpm song at you with flashing lights in the background.
This is probably my new favorite rhythm game. I know there are various improvements in the sequels with different note types, extra singers, and more QOL, but this game is surprisingly forgiving of the learning process and lets you take things at your own pace instead of forcing you to replay hard ass levels from the start and making you deal with it until you're good (though, that's probably just me being bad at rhythm games.)
Something about there only being 4 buttons made this game very engaging to me, It's like ddr but without the headache of trying to find the right arrow. Now that I'm thinking about it that's probably a little dumb because the buttons are in the exact same order, but for some reason the face buttons are much more simple to grasp for me than the corresponding arrows, especially at such high speeds.
The track list is fun but definitely not anything to write home about. The game came out in 2009 when vocaloids were still in a weird state of pseudo-infancy and because of that most of the songs are by the same couple of producers that were popular back then. That and what seems to be an entire section of songs that were just really popular on japanese internet at the time.
Overall I think the simplicity of this game really helps it, even though some fans of the series would probably disagree with me. I love the colors and the cute anime girls, so this is the one time I'll allow my random vocaloid hyperfixation from middle school to surface and shine in the spotlight. Hachuche piku ftw.