I would have it based on Vermilion and keep the resistance and weakness used there, all you would need is to have maybe two or 3 attack options as well as the grid based movement and it could be really simple. I am thinking the old school pixel grid landscape (for nostalgia sake) and then the minions, so almost like they are playing on a board set or generated map. That way there is minimal effort in animations for the minions and the backgrounds and settings can be varied and nostalgic as hell... caters to fans and newbies alike I would think. I mean who doesn't love charming retro pixel based graphics thrown in now and then for aesthetic effect?