Shit to Make Sure Of:

Identity Concealing
When Hiding The Character's Identity Throughout The Game, Make It Pretty Much Impossible The First Time Through For Anyone To Guess. But Their Second Time Through, They Should Kick Themselves For Not Seeing It. Kind Of Like M. Night Shylaman's Films. Maybe addodd little things here and there with two complete sides, the visible assumed side, and the secondary later-discovered perception change. Basically, make two tracks of the plot. One that the player/buyer sees and assumes, and have this series of events, at least a few of them, with no loose ends to question without a good answer (like the piano & door scenes of the others), leading to the second plot that walks over the first one in reverse. Explain Loki's Purpose In Ch.5 or Ch.6 (About Sage Breathing), maybe in second game, and also, earth's nuke that hit the lokust sun. Keep that out until later? Now there's another reason for Loki. Now he has vengeful character and reasoning, also something to second-look from your new earthborn perspective.

Loki's Knowledge
Loki is not to know anything at all, and be reborn as an earthling so to speak. He cannot know anything, everything must be found from what he assumes and what is told. obviously, his assumptions aren't always right. All conversations with those that know either george lewis or loki, will be somehow blinded. For example. tortured earthlings on triax will have their eyes sewn shut.

Evil Visions with small deliveries at first
Upon first landing on Triax. There should be few enemies. The enemies that do exist are all animal-types. The aliens themselves are mostly peaceful or nervous.

The Existance of Mirrors
Prior to Chapter 7, or well, most likely, game 2, Any mirrors should be in dark dark areas where our player can only make out his suit and nothing behind the glass. I don't know of any mirrors in the first game though, well maybe in the opening house bathroom (which could be turned off or broken or something).

The Obviousness
Indians make it more obvious than the triaxians perhaps? I dunno. This story needs to be handed over to someone other than my mom that doesn't know the ending. Here's a good idea: Try not to hint that there is a suprise ending that has to do with your identity. It's already going good so far i think, so this shouldn't be a problem. Just don't have the player ask two questions in a row, one having to do with not knowing where loki is, and the other pondering who you are. Something like that. Bad Idea.