I enjoyed the game. Though figuring out what the black monsters and purple stars do is part of the fun, I would really suggest designing them in a way that communicates their functions (Didn't realize the monsters could destroy the altar and lost all my progress. Then I felt frustrated and did not think I could do anything to stop the monsters until way later when I tried out the purple star).
Repeatedly dragging humans to the altar felt like a lot of busy work, especially in later levels. The players should simply win by reaching a certain population. I like the trade-offs for deciding to collect different kinds of resources, but the consequences for each decision did not feel significant enough. Lastly, I'd be happy to see more player agency since dragging stuffs around gets tiring after a short while. Giving the player the ability to create an optimized, automated system would be way more fun. (Not sure how you'd do that though. Maybe add in something like the programmable worker bees from Slime Rancher that automatically take humans from one specific location to another. The players can then focus on combating monsters later on in the game.)
Great job overall. Best wishes!