What if the Half-Life 2 world was full of antlions and antlion guards everywhere, people were locked up in their homes, antlions slowly destroying cities, and the Combine were the salvation, rebels fighting with the Combine to kill all of the antlions?
That means they would have to have normal people instead of cyborg humanoids inside soldiers, cops that look evil but are really kind and that.
leave it as it is, but make them even more evil. I'm sad why I didn't see public executions in HL2.