For the first part; chose cube because I just highly prefer starting levels off with either cube or ship, due to ship not being an option I chose cube, Didn't choose spider or UFO because I wanted to end the level with spider, and didn't use UFO because of the gameplay restriction of only using basic blocks. (also used 2 H blocks for the cube just for sync, that's all I promise)
Second part, Didn't use robot or wave because the song fits better for mini wave than normal wave which I'm not allowed to use so didn't want to use wave, also if I did use wave I'd want to use blue orbs which again, not allowed to use. And didn't do robot because once again, I can't use orbs. Just did ball for better sync
Third part, used ship because I was already getting tired of only using grounded game modes, didn't use swing cause it feels too slow to move and works better in 0.5x speed parts, and didn't use UFO because of the limitations of not being allowed anything but basic materials for gameplay.
Final part, did spider cause I wanted to do a terrible final click and spider was the easiest to do that with, also again better for sync, my reason for not using swing carries over, and I feel like a broken record, but didn't use robot because I prefer making robot gmp with orbs. Also had a 1 second cube at the end with no gameplay, mostly so the spider couldn't go back up into the weird slope click, also so the player could see the mandatory GG at the end.