Promptitude, my best level! (Demon Difficulty)

Nice level :^). Let's get to the review.

Gameplay 9/10
The Gameplay in this level is very fun, actually. The transitions in this level are quite well-placed and aren't so cancerous and leaves players to react fast enough to adapt to the new gamemode they are placed in. A ton of somewhat original gameplay ideas especially in the duel are in this level. No cancerous jitterclick are in this level either, so I'd give this aspect of this level a 9/10 for fun and somewhat original gameplay

Design 6/10
The design of the level doesn't vary at all. You used the same style of blocks and obstacles all the way through the level which is a no-no in level making. Try to vary the design of the blocks by using different blocks to fill in the black areas of the blocks, or different colors to make things pop-up a bit. Also, this level's design is what I classify as "a bland, unoriginal 2.0 design", So try mixing up your style the block design a bit more, yeah?

Music Sync 9/10
Although the block design is bland and unoriginal, the music sync in this level is near flawless. I like how the blocks' line and background change colors to the beat of the level, which is a nice little touch on your part. Of course there are some parts of the level that did not sync with the level perfectly, but overall the music sync here is perfect. Also, I can tell that you copy+pasted the color flashes during the drop, so don't make that common error either. Instead of using only 5 or 6 colors, why don't use the whole color spectrum? That help make it seem less repetitive to the eyes of the common player.

Overall 8/10 - Feature-worthy (low-end)
This may be your so-called "best" level, but there are still some things to clear up about your levels. So improve your block design and you are on your way to get your first featured level in no time! Keep up the good work