Nice work! I like the stealth gameplay, the sense of rebellion and resistance to the oppressing forces!
To be honest I'm a little unsure about the theme. I love the writing in your design document about "silent rebellion and hope" and to break rules as a form of necessary resistance against the forces destroying or future and planet, however I don't think picking up trash entirely captures that idea. The problem is that our whole society is built on capitalism and consumerism which necessarily creates endless waste, and picking up trash is not outlawed and does not in any way threaten the system.
Waste management is of course important, these are things that we need to sort out, but if that is the call to action I think it would be more interesting to focus on the societal or systematic aspects mentioned a few times in your design document. Why are companies allowed to pollute our word like this? Why have our governments not done their job and made sure we have working systems for waste collection and recycling?
Maybe you can adjust the framing slightly to an action a little more relatable to rebellion in the real world? You could be sneaking into industrial areas and exposing their pollution to the world in order to take legal action or build a movement against them?
Sorry if I'm being difficult. I just really like the theme of rebellion, activism and resistance, I think that's vital if we are to have a future, but at the moment I have difficulty relating the actions in the game to the action that needs to be taken in the real world.