Thanks for playing and the feedback.
The number of resources were due to the theme. They were meant to represent all the random junk from around town that was being used to create the towers and upgrades. We had planned to expand on it by including some crafting elements where you actually used them to either build the towers, or research them, but none of what we came up with, that we could do during the jam, felt like it would make the game better. It felt like shoehorning in the crafting and would slow down/interrupt the gameplay, making it less fun overall by trying to force the theme in. In the end, we favored making a more fun game and went with typical tower defense gameplay, with the theme being mainly in the setting, story, and types of resources used. For us, making the game more fun was a higher priority than a high theme score.