Originally Posted by katsalia

Is your game not super small? On Firefox the game is small and had a black box in the background for 50% of the screen

No it is not smaller than other Nutaku games and there is no black box.

Linux was frozen at Flash Player 11 (with some security updates) by Adobe years ago so maybe the different flash version explains it.

It looks to be the same relative size on Chromium but the computer I tried that on has a much screen lower resolution so that is not an exact comparison.
That computer is really slow so I set quality to low in flash to get it to run less slow so I can't say if it had issues with image quality.