Fun- Had good fun, would play again. Interesting implementation of lose conditions. There seems to be a few bugs with the last few researches though.
Balance- Felt great early game, had a consistent sense of progress. Late researches feel kind of time gated and sandstorms are way too powerful and disruptive even with defense imo. Walls didn't do much.
Uniqueness- Even if it is a pretty generic building mechanic, researches and expeditions add some spice to the mix. Expeditions not so much though, kind of underwhelming except providing a source of metal (which I assume you would get from smiths if they were properly displayed anyway).
Theme- I'll be honest, there's not much going for it other than time passing and being a thing. Would like to see stuff like seasonal changes, add other weather such as scarce rain which briefly turns some sand into dirt? There could be more going on here, I'd like to see this concept get expanded.