This game truly could make a great movie if done right. I'd change a few details though.
For starters, I'd make both Scarface and Hunter Borgia women. Assuming female predators haven't already been introduced to the world by then (or any previous Predators revealed to be female), then Scarface should be the first ever female Predator to grace the screen. The story would remain largely the same otherwise.
Both Scarface and Isabella Borgia could take turns narating the story.
Those three ronins would be killed by Scarface. Perhaps she/he/it could take one of these assholes' swords.
Since this is a movie, it can't be limited to Scarface slaughtering people, so you'd have more scenes fleshing out some of the characters, such as Hunter, Lucretia and Bruno.
At the end, when Hunter is beaten he/she will activate the self destruct sequence and laugh maniacally, followed by Scarface destroying the gauntlet with his/her/it's wristblades, or cutting Hunter's arm.