it's a full version of windows, Microsoft wants as much OS migration as they can so they can develop more applications and attract developers back. it's not like a trial version with limited functionality, it's just the first time windows has given an OS upgrade in this model, it's the same as the OSX upgrades for Mac
as far as free games and stuff idk, you will probably have to search for the specific games or applications to figure out which ones have changed. I haven't looked to see if there is a master list or anything