"Main Theme - Tetris 99" is a high quality rip of "Main Theme" from Tetris 99.
Joke[]
There is no track called "Main Theme" from Tetris 99.
The video plays Verbalase's "Low Tetris" Beatbox Instagram video pitch-shifted to "Meet the Flintstones" and, from 0:24 to 0:35, the Inspector Gadget theme.