I would love to see Star Force on Colecovision. And the difficulty is not a problem. Star Force is for great "shoot'em uppers" who love Caravan Stage and love the PcEngine shootings! Trials/errors, etc.
But I completely understand to make a more praticable Star Force version on CV. Perhaps a selecting difficulty will be a good thing and add a special ending for the players that are good enough to beat the game in hard mode?
It could be great to add some variants in comparison with the original version, to add to the CV program an additional value, in order to keep the interest? It could be just a time attack mode, an extra-level, etc.
To summarize, be sure I'll by this game. Shoot'em up are my favourite genre!