There's a comparison floating around from the first ever screenshots for the Xbox 360 version of Rise of the Tomb Raider. The highlight is that the Xbox 360 version of the game is actually a lot better looking than you may have been expecting.
NeoGaf offered up a couple of comparison shots between the Xbox One and Xbox 360 versions of Rise of the Tomb Raider. The screenshots are impressive, to say the least.
In fact, the first comparison shot actually had me stumped for the longest. The port house Nixxes Software did a really great job in getting the game to look almost as good on the Xbox 360 as it does on the Xbox One.
The most impressive thing about the 360 port is how Nixxes appears to use fog and the draw distance to mask the system's limitations. Although it's really tough to tell just how the LOD is handled given that the shots aren't full screen. It would be really easy to tell the differences with 720/1080 screenshots.
You can definitely see the differences with the second shot, as you can see below the Lara in the top screenshot has has a higher poly-count – notice she has more flexibility and polygons in her elbow in the top shot compared to to the lower shot, and she also has the added dirt and grime.
As you can see, there are also most ambient lights and occlusion in the environment in the upper shot, along with some physical-based lighting emanating from the fire that's spread throughout the area in the upper left hand corner of the top screenshot. There's just way more environmental ambiance and activity happening in the Xbox One version of the game. Heck, even the knife Lara is holding shows light reflections, such as the reflective glow from the moonlight.
The last shot would easily trick most players into thinking both the Xbox One and Xbox 360 versions of the game are same, save for a few very notable differences. For one, the mist in the Xbox One version looks volumetric where-as the one on the Xbox 360 screen at the bottom looks like a collection of alpha sprites.
The actual environments nearly look the same, though, and it's impressive that Nixxes was able to achieve that level of parity between both consoles. The real giveaway, however, is that there is a heck of a lot more geometry in the rock surfaces in the Xbox One version if you look closely enough. It's tough to tell from the size of the screenshot but it looks as if there is some tessellation across the cliff surface on the right side of the screen.
The other obvious giveaway is Lara, of course.
You can see that in the bottom screenshot the lighting is pretty basic and doesn't feature the same level of soft self-shadowing as Lara in the top screenshot. You can also see that her hair has more detail and breakpoints for physics-based sway in the top screenshot. It gives the hair a more natural look compared to the stiff hair physics from the previous generation. There's also some obvious texture quality differences as well between the two Laras.
Rise of the Tomb Raider is due out this fall for both the Xbox One and the Xbox 360.