One thing to consider about this, is that in the film the game is basically a training sim for people to fight the Ko-Dan. Now since (IMHO) the Star League figured their squadrons of starfighters would defend them from the Ko dan, it's possible to assume that they never saw the possibility that Starfighter Command itself would come under attack.
Having said that, since there's "hundreds of worlds" in the Star League, it would be safe to assume that perhaps knowledge of the Ko Dan "meteor gun" was attained through espionage.
Following that, for another section of the game, perhaps a colony or outpost could come under attack and you'd need to destroy the incoming "meteors."
Since in the on screen game we see Louis get taken out by a missile, perhaps there could be a "mini mission" halfway in, where a Ko Dan missile carrier or torpedo fighter is launching missiles at the player. The player must dispatch a set number of waves of missiles, then defeat the "torpedo ship" to complete that stage of the game.
If you're allowing a user selectible dip switch setting for difficulty, these two suggestions could be adjusted up or down in difficulty depending on the dip switch settings.
Keeping in mind that Alex (in the film) is assumed to have been playing this game, say, all summer. It makes sense that the game would be difficult and that him reaching the "Record Breaker" screen would take some effort. Now, if you're not that good of a game player, you could turn the difficulty down and reach the record breaker. Or, if you're a "gamer," you could turn it up and make the playing time worth your effort. No good (or great) arcade game ever let's a half hearted player play all the way through on one token. It rewards lazyness.
Have you thought about adding a "high score" table and retaining the player's high scores, even after power down?
Most games from that era (1984) did not retain high scores, but personally, I'd welcome the ability if it was offered. Or for the perfectionists, leave it as a user selectible dip switch setting, to save the scores in RAM until the power drops, or save it to some non-volitile (NVRAM) style source. Or somehow save it as a TXT file? I don't know, I'm just tossing out ideas.
As always, the progress keeps looking better and better with each passing month! Thanks for the effort!
Rook