The defense is perhaps the most similar part of the game in comparison to the demo. The new inclusion being the dominant tackle feature (The S button on the kboard). I find the S button to be just as effective as the F button as it tells us to use in the booklet. Once you make contact repeatedly hit S as this will decrease the chance of an offload.
Also, I find that rushing up is a no no as the opposition gets around you effortlessly, this is perhaps where the game really falls flat on it's arse. In previous League games you could co-ordinate your defense and hardly found yourself aimlessly bashing the keys in trying to stop the computer from scoring. Now some may say it's because I'm not used to the controls since I've only played this game for 1 day, but I had the same problem after months of playing the Demo. I find it hard to keep up with the computer with all their inside balls at Harlem Globetrotter speeds and zippy swerving & stepping skills.
The only way I have found to combat this is to slide across in defense and try to get a good player change system going and then immediately press tackle. Close to the line this is sometimes not effective as they will throw a few inside balls and before you can say wherethef**kdidhego he'll be around you and scoring a try. Quite annoying if this is the only way higher levels can score tries. Obviously, with hours and hours of practice we will uncover doggy tactics and keep even the highest skills out, but at the moment this is all I've come up with.