Thank you very much for taking the time and playing the demo, this is some fantastic feedback! Generally I agree, I also taught that it's difficult to know what can be picked up and what some of the powers ups do exactly. For the second one I'm working on a dedicated and detailed stats and build screen and a full power ups tree that'll show what each power progression looks like an what each tier does.
I will try to address most of these issues in the next demo hopefully!