Short Arcade like game.
Frame it as Doom. Demons, and monsters are everywhere doing terrible actions.
As you go shooting, looting, and finding secrets they start to look more 'human'.
The 'human' appearance is related to how many horrible deeds you see them do.
Revealing the truth.
For a long form game. Harvest moon type game, and/or Papers Please.
To maximize the impact there should be a build up.
First intro is seeing the relationship in action. Normie McNormalPerson finds himself a plot of land (or a job). He works to make ends meet.
Gradually outside forces make it harder, and more difficult to work.
Eventually he is pushed so that the job/work/lifestyle just isn't sustainable at all anymore, because of their actions.
The world gets vastly more dangerous unless some preventative measures were taken earlier in the game.