Dance by Geogamer12, Zac2605 and Eternalyz
Since this is a collab level, I'll split the review up into the three parts.
Eternalyz's Part - 0-52%The gameplay in this part isn't very good. The black flashes at the start is a bit frustrating the first few times playing the level since it covers the screen before suddenly throwing the player back into the gameplay. It would be better if the gameplay up to 1 second after the black flash disappears was auto so that the player has time to get avoid the obstacles.
After that, the gameplay is pretty solid until the ship at 21%. Moving backwards is a gameplay idea that's unfortunately been done many times before, so it isn't original anymore. Most of the screen is covered as well, forcing the player to have to memorize the obstacles to get past the part. Keeping the moving backwards gameplay is fine, but the blocks that cover half the screen should be removed, or at the very least kept to the edges.
The wave immediately after also uses another bad gameplay mechanic: ultra slow speed. Gameplay which uses it usually ends up very boring and tedious to play since they usually end up just waiting for the obstacles to come. While the part is short, avoid using that kind of gameplay in the future.
As for the decoration, the effect concepts are pretty nice but the execution could be improved. The biggest problem are the colors; most of them are too saturated and stick out too much. I highly recommend using blending on them to make them blend in better with the background. You can also change the colors and opacity until they blend in well and they don't look too saturated. The first cube, robot, ball, and wave are also pretty empty and could have more foreground decoration like sawblades, blocks, and spikes to fill it up. Finally, the star effects from 43-52% should be in the bottommost layer to avoid them overlapping the blocks.
Zac's Part - 53-72%Gameplay-wise, this part is pretty solid with some decent but unremarkable wave and UFO gameplay and almost no unexpected moments. The transition to this part could be better done, though. The obstacles should be pushed back a bit farther to allow time for the player to reorient themselves.
Decoration-wise, the effects are executed quite well here, with good colors and decent block designs. The emptiness problem is still present, though, due to a lack of foreground decoration. Adding some sawblades that fit well with the custom background can help to fill things up.
Geo's Part - 73-100%The gameplay in this part is a lot more interesting and doesn't really have any unexpected moments. However, the transition to this part is very random and sudden since the teleportal is invisible and the player has to react quickly. Making the teleport all visible and putting a blue pad before the spike to make it auto can fix this,
The decoration and effects are quite good as well and it's definitely filled enough, but the sawblades placements are a bit disorganized and could be spaced out better so that they don't overlap with the blocks or each other. The very last rainbow part feels very out of place in the level as well and should probably be redesigned to continue the space atmosphere of the previous parts.
Music SyncVery good, actually. Many cube, ball, and robot jumps sync well to the music and the transitions are timed to it as well. The designs fit the song too, if a bit inconsistent.
OverallThe first half could use a lot of improvement. The second half is better but not exactly remarkable as well. Music Sync is great, though.
Decent. 
