A few tiny niggles already. Startup resetting the VIC-II and displaying version number means that the default colours for border and backround are set. Better keep as black to prevent the blue flash.
In game holding F1 to cycle the colours causes the screen to glitch as $DC01 is not checked against being equal to the previous value before changing colour.
Yellow screen means that the score is not visible.
You should pad the CRT (ie unused space) with $FF and not $00.
