Offer an option to become a
'Subterfuge Champion' or whatever you wanna name it.
Cost $100 USD
Benefit: a beautiful gold outline around all of your factories and or generators.

P.s. sorry if this is in the wrong place.

and probably all your subs and mines and projected trajectories and specialists and shields as well
I would probably call it a 'sponsor' cause that's basically what your doing.... Oh and maybe I'd say reduce the price to $25 (less benefits) or $50 (more benefits)?
Maybe for the higher option you can customize the colour, and for $25 you get to choose between silver, white, black, blue, and a few other colours maybe?

And maybe some kind of "medal of honour" that appears on your info panel somewhere if you sponsor.

I'd pay for this.....

I mean i made $300 working overtime for 7hs today so sign me up!

I am totally hooked. Even though I play one game at a time, I am spending easily 3-4 hours a day playing Subterfuge. I tend to price a game according to the pleasure I get for it. And for Sub, its... wait for it... LEGENDARY

So yes, I would pay anything to keep it going. I would prefer a very discreet indication (it could just be a L3 clearance not to spoil the minimalistic design of the game

I see a lot of talk about monetization. I am in the view that Ron and Noel have put a lot of love in designing this. I think that people who were able to design such a deep game have plans for keeping it running till the next century