This is one of my favorites in the entire jam thus far, its already very good and keeps you going and has a lot of room to grow for a full release (which i'd be very excited for)
even just adding more monster types and (maybe tone down a bit the almighty ORB) to add more defenses or even new resources) would create more build variety and in general complexity.
(only minor nitpick if i had to say is the tutorial its not really well done if you do not follow it you can get softlocked)
This being your first game jam though very good job!