You can follow the official server for news on mobile development. Do not ask for APK links there (it is against their rules), but you can learn about legal ways to play.
The community provides several mods to improve performance or add features: How to make the game WAY less laggy with the power of mods Project Arrhythmia Apk
Abstract, colorful art styles that react to the music. You can follow the official server for news
Q: Is Project Arrhythmia Apk free to play? A: Yes, Project Arrhythmia Apk is free to play, with optional in-app purchases. Q: Is Project Arrhythmia Apk free to play
A massive library of user-created levels.
Project Arrhythmia APK — guide to what it is, how to safely install and run it on Android, legal and security risks, and alternatives if no official APK exists.