The game is very tight and polished, and the music is great, an important trait for a rhythm game. The sudden combo color shifts can feel a little unfair depending on when it happens, though I understand that between locking a combo and generally just keeping track of what's coming, you can respond to it if you're fast enough. But for me it just ended up being a little too much to keep track of, and didn't add much to my experience.
Moreso, while the line BG effect is fun, the random colors were very intense and often irritated my eyes; Sometimes this would inhibit my ability to keep up with the game. If the color changing persisted, but used slightly darker/less saturated alternate colors, I'd probably have an easier time handling it.