Holy moly, what an amazing game! Played through three campaigns (and three skirmishes), the last campaign (on hard) I actually won, that was really fun! First the orcs got squashed, and then the human leaders, one after the other, betrayed our alliance and I managed to be on the winning side in each matchup. At the end, it was a 1v1 with equal number of lands, but I had levelled them more and got the upper hand. Great game, crazy that you made this in a week!
Some suggestions: The diplomacy part could have more weight. Alliances are easily broken and once an all-out war starts, there is no way to befriend one nation to fight against the biggest competitor (or something like that).
Also, I didn't know what the different units do, some explanation there would be nice.
I did not really use the zoom-in mechanic, it feels really cool to have something like that, but I feel like it is kind of unnecessary (at least as of right now).
Anyways, I am excited to see where you bring this game after the jam, there is a lot of potential here.
Oh, and this game reminds me a bit of LandGrabbers, but with more layers of complexity involved.