Ghraphics were not really improved but gameplay was improved.
16 April 2013
Summary: The game is fun, the rosters are updated. Gameplay has improved and has become more intricate. Graphics remain the same since 09 in my opinion. Nothing really significant to notate other than the fuller control.
It's still the best in the NHL series despite some minor annoyances
17 August 2012
Summary: Since the 2K series is no more, all we have is an EA monopoly on some sports games. Luckily they treated NHL 12 differently than Madden. We have some nice updated player and puck physics from last years. Checks look more appropriately animated as well as goalie movements. The standard controls have not changed, by means of right stick is the stick movement and left stick is the player control and aiming.The Winter Classic addition is kind of cool.
Summary: NHL12 is a pretty good game . If you're going to buy a hockey for the roughness choose NHL12, if you want hockey for its game choose NHL11. this game has changes in goalie interactions and roughness play including shattered glass. Size also matters, so if you're St.Louis and you hit Chara you might lose your stick or fall yourself. One main problem is freezing. it happens on both x-box and ps3, so if you want uninterrupted play get NHL11.