Hey Robin!
The character upgrade came from wanting to add character abilities like Pandemic but not having them rigid like the class system there. Flexible upgrading feels more rewarding and allows different players to prioritize different build paths according to preference and situation.
Thanks for highlighting the issues. I wrote the rules hastily and didn't include any examples :-/
You lose the game when the number of garbage is equal or more than the loss state on the game progress sheet according to current stage. For Stage 1, you lose at 28 garbage on the board. For Stage 2 at 26, etc
The winning conditions made more sense?