Game suffers from severe slowdown as reported by multiple users. Can cause the game to become very difficult to play and progress through. 

Solution submitted via website

Working in RetroArch with PCSX ReARMed NEON core

These were the optimal settings:

PSX CPU Clock = 70
Enhanced Resolution = On
Enhanced Resolution Speed Hack = On
Latency > Frame Delay = 3

Website User Report:

With these settings, I managed to make it all the way to Stage 5 (the bathroom rap) without issue.

There is a screen flickering issue when failing a song (or manually ending it by pressing Start), however. By the way, please use RetroArch. The stock emulator will fall out of sync every time your rating drops or increases, thus rendering the game unplayable.