In longer play do you imagine there are other towers? I guess it strikes me as very much like 28 Days Later.
And I was going to ask a question about the coins but I think I get this now. I get one quad free, the other three quads take one type of coin each, and I can stack up to three of the same type and have "stacks" as a quality.
So, I have to balance how many different types of thing I stick in my bag (and decide what penalty to my mobility that I want to live with), and try and get stackable coins of the same type.
I can see the MC offering me quarters when I want pennies and dimes.