I must say this right off the bat: Gumi's English singing is more tolerable than Miku's.
Now, back to the song. I was at section (a) when starting this review, and right off the bat, it sounds like a breathtakingly twisted combination of Balalaika (from Kirarin Revolution), circus music, Ghost House themes from New Super Mario Bros., and anything that you hear in a boss battle with clowns -- the most notable example being the Super Demetrio boss battle music in Super Paper Mario.
There's a beautiful dynamic flow between sections. I especially liked what you did with verse (a), getting soft again, having the 'gizmo' sing by itself. I also love the instrumentation A LOT.
My main queries are with the lyrics. I loved verses A / a and the choruses (C), but I'm not sure what B / b refer to. I wonder what this pink gizmo actually is..... It's nothing that can gash my listening experience though, because I enjoyed it. I am curious, what's the story behind the song?
I'm giving my score on musicality alone, because I can't tell on lyrical grounds. Apart from ZipZipper, it's not everyday that I hear songs along this vein. And you pulled it off quite well, musically.