Fahrenheit Storyline Rant

The storyline for this game was unfailingly brilliant and engaging. Right up until the third act, which was shit. Major spoilers following:

Carla falls in love and does naughty things with Lucas in the undeground station:

What the fuck? She just met him and the sum total of their conversation has been some babbling about being possessed and innocent, followed ber shouting “Over here!” and pointing to a manhole.
He’s dead, dude. She even says he’s like ice. That’s just nasty.

Possible interpretation: Agatha’s not really dead. She’s a disguised member of the Purple (or possible Orange) Clan:

Who the hell are the Purple Clan?
How did they manage to maneuver themselves to be the buddy of the guy who can find the Indigo child if Lucas was just chosen because he was in the wrong place at the wrong time?

Possible interpretation: Agatha is dead and the Purple clan guy is impersonating her to get to Lucas:

Fair enough, but what was the point of killing her in the first place? (This also applies above) All that did was bring the cops down on Lucas, which admittedly made for a great-looking action sequence that I barely saw since I was furiously bashing buttons, but it didn’t provide any advantage to either of the factions chasing him.
The game is full of great realistic-looking people and backgrounds and then we get a glowing guy that looks like he escaped from an early rendering of Hollow Man. What the fuck?

The fate of the world is determined by whoever puts a creepy catatonic child on an altar: