Music doesent stay muted, it turns on when you reach the next level or if you refresh the game.
You lose the game if blocks reach either top side of the screen. Im probably nit picking but it just seems cheap especially if you are building walls on either side.
Sometimes the starting block gets stuck if you restart the game but you can fix it by pausing and unpausing.
A completed row failed to disappear and pretty much killed that round for me.
The delay on the power ups are sometimes way too long like for example the filler block.
Fun game, far from terrible.