Hey, thanks for the feedback! I completely 100% agree with your analysis. There are a lot of things I wish I had time to do to help the player understand what is going on. The game was just boxes and darkness for all but the last week of development. The game missing a UI makes it very confusing. The auto spawning is a result of there being no UI so I had to give the player something to work with automatically.
The player has a money resource which I call Energy, and each unit can collect them. The models weren't displaying though when I submitted, so all I can say is that there is one energy deposit right by the spawn point to collect from.
There is another type of resource system that is currently hidden, but if you pay attention, you might notice that your first few units are moving faster than ones that spawn later. That is due to an upgrade system where units in an area belonging to a particular stat gain bonuses over time (once an amount required is reached). There is one for Health, Attack, Speed, and Range, but good luck finding them without any visuals xD. The AI has one near it's spawn point that is giving it an attack boost for example.
I am continuing to work on the project, so I anticipate having a much more playable game soon. Thanks for playing!