Put a quick fix for this. Garbage collector tends to slow down interval between sheets. Added reverse sound to the level completed hook. Ended this loop hole. The lander fire quicker bomblet to attack the player.
Bomber are more voracious too.
This is the length of the sound data buffer used to generate the sound. So you can't cheat. Increase the game over screen delay. It was far too short. However this not the only contentious problem with the browser.