Emulator

Alsa has a higher audio latency compared to Pulse. See this: https://stackoverflow.com/questions/29245583/alsa-vs-pulseaudio-latency-concerns.

I attached a demonstration video to make the comparison. In the video, audio tracks of the two clips are aligned. The left one uses ALSA backend and the right one uses PulseAudio. You can see, that the left one has its video ahead, meaning the alsa audio is lagged.

Such audio lag is enough to make a very bad and very notable difficulty for rhythm games. With ALSA the music is totally wrong and you will get all misses when play the game Rhythm Heaven.. - That really confused me for a long time and I spent a long time then finally found this is caused by the ALSA backend.