Cube
I used the cube because it's the easiest mechanic to learn in the game, but also good for timings and buffers.
Ball
I used the ball because of its sharp movement up and down and also to make the gravity upside down while going into the next part.
UFO
It is very good for timings and also small spam parts as seen in the level. It is also easier to sync up with the gameplay.
Spider
Same explanation as ball, except that the spider has an even sharper movement, which can lead to precise clicks seen in the end of the level. + usable for sections with high CPS. Placing the spider also made it so that your not stuck too long upside down.
Other Gamemodes.
I didn't use the gamemodes like ship swing and robot, because without orbs or other gameplay elements, they would feel too floaty for this level. The wave is a good pick, but it would feel too bland without any gravity changes, so I instead picked the ball which can change gravity.