SPOILER ALERT:
Another thought: What if you were unkowingly helping the big bad? Like Cassie in FNaF Ruin? She unknowingly released the Mimic when she went to the Ruins of the Pizzaplex to save her friend, If not, why don't we add a challenge like that? Why not add:
"Make a game where you accidently help the villian"
I'd say that would be rather fun! :)