Your gorgeous photo is on Reddit as well and has generated quite a bit of discussion over there
. Key question: why is the game off-center?
That’s just the way the game is - I assure you it’s not the monitor alignment.
Both the title screen and game itself are aligned left - definitely odd for an Amiga game I know. If you check Youtube play-throughs you’ll see it is the same even on emulation. I could have adjusted the monitor to centre it but then I would be messing with how most folks would have seen the game back in the 80s (unless they were adjusting the monitor controls for every game).
And just to prove the point, here’s Captain Blood which is using (I’m guessing) the more typical 320 width. No monitor adjustments were made between games.