I install my flatpaks as a user, one time I updated my system and I got all my installed flatpaks back with my home backup. I did a system reinstall again, changed the distro, and got all my flatpaks back again, everything was looking fine until I tried to play some games, there is no sound in any game. Some outputs:
Could not open audio device
Sound init failed. Using nosound.
ALSA lib seq_hw.c:466:(snd_seq_hw_open) open /dev/snd/seq failed
Initializing sound: failed! SDL Audio: error in Init or InitSubSystem.
error << ack, sdl_init failed: Could not setup connection to PulseAudio. >>