The problems with this game run much deeper than any lighting or texture improvement can overcome.
The first few levels makes you wonder why everyone is being so super critical of the game but after you get to the back end of the game you can see that they really dropped the ball.
The game itself plays like a highly polished mod, for a triple A title it feels like they needed at least two or three more passes to polish everything, add in some scripted events like they showed in the demo where marines are pulled into vents and killed, improve the AI of the Aliens and replace the apparent placeholder objects they put in the game to fill in dead space.
You could make a drinking game for every time you come across a cup with pencils and scissors in it or a generic craftsman toolbox and be shitface drunk half way through the game. With many of these objects floating above tables.
I still can't get over the six years of development and how far off the final game is from that early E3 demo.