It was made and designed for the PC, the port to 360 was done by another company and done very poorly, it is not a 360 port.
I was referring to the behavior of supporting 4:3 and 16:9 perfectly and then lumping all other aspect ratio support under those two. A lot of 360 ports have this problem. It was not meant to slur the game, just the behavior.
And I don't really see what you are saying with the HUD, it looks almost identical, maybe slightly thinner, but 16:10 is a thinner res... neither looks stretched at all...
And that is the problem. They should be the same dimensions exactly. The size of the elements can change in some cases between aspect ratios but they really should not. Most of the time they should be the same size and dimensions if the number of vertical pixels are the same.
So a 1920x1200 pic and a 1600x1200 pic should have a HUD of the same size. As you can see by the health bars the 16:10 is narrower then it should be because it is using a 16:9 aspect ratio instead of a 16:10 aspect ratio. It is in fact stretched vertically, or compressed horizontally, whichever sounds cooler.
EDIT - If you are having trouble seeing it look for simple shapes like squares and circles to compare. In this case, use the gold coin in the inventory box.