Excellent foundation! All you need is some variation, but I won't blame you if you want to keep it as simple as this. The appeal of minesweeper over an RTS is about being able to take your time to contemplate your moves, while also being able to pick up and put down at anytime. While I do think what you have is solid, I do believe that some improvements can be made to the UI, as I am completely inept when it comes to the original so I had no clue what each number represented on the overlay, but that comes down to me being stupid. Just a cherry on top would be some more variation, to enemies and units, maybe make more advanced units, maybe something like a Chaplin (an obvious stand-in for bishop) have a diagonal movement and replenish unit health, again just some added types while incentivizing movement and exploration, perhaps a Hunter who slowly digs and stalks along the cave walls, waiting for the Refinery to be unguarded in the corner. Just spitballing cause I already love the concept.