Cannon Fodder Christmas Edition is actually a two level special edition of the original Cannon Fodder game that was originally featured as a bonus cover disk with Issue 54 of Amiga Format magazine. It is sometimes also referred to as Cannon Soccer (you'll see why later on).
The gameplay remains much the same as the standard game - you have a group of four soldiers who you control with your mouse either as a group, or split them up to work individually, with the aim of wiping out all the enemy soldiers in the level using guns, grenades and rocket launchers in order to progress to the next stage.
Of course, they aren't going to go down without a fight and they will use all their AI in order to attack, ambush and pick off your soldiers in return.
However, as this was released as a Christmas special, the game does have some slightly different features. First of all, both levels are played in a snowy landscape, with the first one ("Land Of Hope And Glory") starting off on a football pitch that should be very familiar to people who have played the game Sensible Soccer (as it was also made by the same company). And sure enough, even the enemy soldiers are taken from that game, in that their sprites look just like Argentinean footballers, even down to the kit!
The second level ("It's Snow Time") features more of the same, with even more enemies to kill, plus you have a large area of water to cross which can leave your troops very venerable to attack.
As there are only two levels, the difficulty is set quite high (the helicopter on the first level can be very tough to destroy), but anyone who has played through all the levels of the original game shouldn't have too much problem - it's only if you are unfamiliar with the game that you will really struggle and if that's the case, I'd recommend going back and downloading and playing that first.
Considering that the game was essentially free, it's really good and ends up being a lot of fun with the Sensible Soccer cross over, but this probably won't hold your attention for an incredibly long time due to the lack of levels. Still worth downloading if you enjoyed the original game or just like shooting football players!