You are correct the image was created by shifting the color space as the Grand Theft auto developer was talking about. Even with just a shift in the RGB values it is easy to see that the lighting on Drake is intense and not just flat ambient light. Look at the variations in the lighting which is not present in the gameplay footage.
To me it looks like the E3 teaser is using much more complex lighting. It is more than just time of day and the sun's position. In the E3 teaser, Drake is lit by the diffuse bounce lighting in the scene.(much more complex) In the gameplay footage, he is lit by simple ambient lighting which results in flatter and consistent lighting over the model. Go back and play the Last Of Us to see what I am talking about . The model isn't lit by the light in the game world. It is lit separately with just ambient light.
It is easy to see this when watching the gamershyde video. Look at how the Drake model is lit as it passes over the shadowed areas and bright areas of the map. The lighting all over the model is consistent with very little variation in lighting as you would get with diffuse lighting. He is lit with just ambient light.
Now go back and watch the E3 teaser. Look at the way the model is lit as he passes through the different areas. He is lit by the diffuse bounce lighting in the world.
In order to demonstrate the difference in ambient and diffuse lighting, here I have lit an untextured white sphere with ambient and diffuse lighting. I hope this makes it more clear. With just ambient light, you get very little difference in the lighting across the model. With diffuse lighting, you can see the variation in lighting across the model. Just remember Drake is textured so you just want to look at the lighting not the texture.
This is exactly what I am talking about. The pics you posted show Drake lit by a diffuse point light at the spot of his muzzle flash. I wish realtime dynamic lighting was present all over the map not just when his gun fires. Instead, Drake is lit with just directional ambient light, resulting a flat consistent look all over the model.
I don't like "downgraded," it gives the wrong connotation. I would call it scaled back. From a technical point of view, the game uses much simpler lighting than the E3 teaser. The models are exactly the same, the lighting is not. The game is still early, so we will see if they will be able to equal the lighting in the E3 trailer in the cutscenes or gameplay.