Thank you for the reply, and glad you are still working on it!
It seems to me that the sound problem appears mostly when using savestates. I'll try to test ot more on different devices. I get this on an Android S8+ that runs other GBA games perfectly. Is this game more demanding?
It feels like the memory keeps filling and then the sound jitter appears.
I tried it on S20 and pc too, but there I only got sone random jitters. I will be back with other test results!
Another thing: to me the lock system is really inconsistent. I think that it's cool that the piece auto locks after about 3 seconds, to prevent the game from being too easy.
But as long as I try rotating the piece and those 3 seconds haven't passed, the piece shouldn't lock. Like it is now it's really hard to play past the 10th level, because one minute you can spin the piece 10 times in that timeframe and keep trying to find it's place, then the next piece comes, you push it somehow into a corner and it just locks after 2-3 rotations, and this really messes with your flow. That's how I always lose a game, and it's frustrating.
Even if a piece can not be move anymore, as long as I press the rotate button the next piece shouldn't drop, cause it just messes everything.
Could you ease explain a bit how the lock delay works?