It’s Age of Empires, with fewer civilizations and you need to both pay $20 and level grind to get full access each civilization. That is for each civilization, not $20 for the game. I can see where this business model would be great for Microsoft except for the “why would you pay for this rather than just buying an RTS?” part. They may have missed the “micro” bit of “microtransactions” with a $20 starting price point.
They are swinging for the home run, though, coming out of the gate with a $100 “season one pass.” They dream big, and MMOs are not the only ones asking you to drop multiples of a box cost for the promise of future content development.
Playing a little further, I met my first item that was no-drop, no-sell, “premium civilization” only. (Storage space is also strictly limited under F2P.) I think my exit point was meeting the Hetairoi, which are basically battering ram cavalry you can access with a “premium civilization.” I think the intent is “look at how awesome the paying customers’ toys are,” but the affect is “pay to win.”