Graphics - superb on the PC.
Optimization of code - superb. Runs fantastic on my spruced up very old system and graphics card (extra ROM).
AI - both your teammates and opposing team's players know what they are doing, and they do it well. They move to cover the runner without the ball on the defense, they run to cover gaps in defense... On the offense, they make brilliant runs for you to pass the ball to.
New Defense System - no more pressing one button when defending to home in on the player with the ball and take the ball away. This new system is brilliant. Tackling is implemented so that when a player commits to it, he REALLY commits to it, and, if the ball is not won, the attacking player with the ball will blow past him, taking your tackler out of the current play. In fact, on the defense, where to tackle, and where to just cover, and where to run next to and try to body check/annoy the opponent are what wins the game here. Brilliant.
Career Mode - Very well done, lots of chrome and polish. Newspaper articles written about your players, team, your league and every other team/league. You will learn if a player is unhappy at a club for whatever reasons (lack of playing time, personal matters) and it will affect your game. The transfer negotiations are give and take, and you have a few tries to get it right - somewhere between what you think you should pay and what THEY want you to pay for a player. Failure means no transfer for you...
Multiplayer - no lag whatsoever. Various modes for multiplayer, with the standard and ultimate team. The latter is quite simply a money grab, but there is no need to get into this whole rigamarole if you don't want to - the game is A-OK with you playing standard multiplayer with your team, trying to climb the rankings. Great fun.
Skill Moves - to win the game, passing the ball intelligently and suckering the opponent out of position works wonders. You DO NOT NEED skill moves to win the game. They are, however, very well implemented, fun to do, they work when trying to pass a defending player, and are spectacular when watching your replays... or online videos.
How do I sum this up... Perhaps this will suffice:
This is the best sports game I have ever played.