This is neat!
Wasn’t sure how much impact I was having, especially since I kept losing the very first level where you only have the one guy, but I understood what I was being asked to do.
Some more info on unit stats/behaviour would do a lot for this, but it’s a solid start.
Found a bug with adding from inventory to shop:
Inventory is initially disabled(?), but grabbing the one in your inventory and dropping it will enable you to drag and drop from the shop.