I actually had high hopes for this one, since it's the most shmup-like in the series, and I've been getting into shmups recently, but it seems to accidentally stumble into nearly every pitfall of the shmup genre while trying to do something unique with it. The fate line as a restriction for movement seems like an interesting idea at first, but it's not well-utilized most of the time, and when it is, it just feels like an extra obstacle that's hard to consider when dodging around bullets. Meanwhile, enemies feel very spongy, patterns of enemies and bullets are slow and uninteresting, power-ups don't change much and aren't placed in ways that they can be strategically utilized anyway (actually a far cry from previous bit.trip games, where power-ups were functionally required, leading to a cascade of failure if you happened to miss one), points are basically useless (since they only contribute to high score, not extra lives or anything), the hit system being tied to attack upgrades means any failure is punished by bosses and enemies seeming EVEN spongier (or a cascade of failure, once the game decides to get difficult around stage 5).
I just didn't have a good time.