Space mining, trading and combat.
What I probably could have done is take the code from this, changed it so the ship just flies straight (no player controls) and grabs resources as it goes and made the upgrade / gun screen more prominent, so the arcade part is like a small part of the window and the rest is numbers and upgrades. So probably could have done it from this without restarting.
I did a sort of 'colony' version but I think it's lost now. There was a simplified Construct version of that but it was too simple.
Yeah, that does sound very easy but I'm not sure if that would even get a lot of plays. I will admit numbers in games can deter people.