The mountainside is littered with the corpses of dozens of cars and beyblades. This game is hard.
I love the idea of performance in one game influencing the other! I think there's a strong mechanical link, but I would've liked if there was more of an explicit thematic one, as well (e.g. the blades are the wheels of the car). It could also get frustrating when I was dealing with a difficult boss fight, so I had to go back and replay a level that was already challenging enough just to beat. It works, but I wonder if a more free-flowing setup race stage (similar to Kirby Air Ride's City Trial) would've worked better for me.