In both cases, these games demonstrate really nicely how developers should create sequels. the best sequel keeps the core feel of the original game, and adds new depth and interesting features.

Call of Duty 4: Modern Warfare 2 is a Titan; it is the largest dollar-value entertainment product launch ever. The original COD4 was something of a sneak success. The single player campaign had all the qualities of a full movie, with interesting and distinctive characters, and varied plot.

What drove the game to real success though, was the multiplayer system. The main innovation of COD4 was that it introduced MMO-like qualities such as XP, loot (in the form of weapons unlocks) and quests (in the form of challenges such as kills requiered for particular weapons). BattleField 2 had some of these features, but COD4 took a much more arcade-oriented, small-squad tactical model. It was twitchier, and combined with the XBox matchmaking system to make a tight game with accessible progression.

The sequel, COD4:MW2 extends the multiplayer and adds a new mission-based cooperative ‘special ops’ game type. If, like me, you dive straight into the multiplayer, the game asks you to consider the single player missions. Infinity Ward correctly inferred that the real meat is in the online multiplayer.

Your loadout in the new game includes an expanded secondary weapon list, including shotguns and rocket launchers. They have moved some of the more broken perks into death-streaks, which are activated by dying lots. This means that you get a chance to come back with a bit of help if you’re having a bad round.

There are also new kill-streak rewards. You can now unlock them and pick three from the list which runs from UAV to the 25-kill-streak, round-ending nuke.

Everything also has a challenge associated with it, all the weapons and all the perks. They give unlocks including thermal sights and heartbeat sensors.

The whole thing makes the game far more customisable, and rewards almost every choice you make for your class.

The original Assassin’s Creed was a great game, but was widely regarded as being too repetitive and a little shallow. On the plus side, the core mechanic of free flowing parkour was the best of any game. The sequel took the criticism head on, and added more side missions and the ability to buy upgraded gear, as well as an upgraded base of operations. While these aren’t super-deep, they add up to a very nice increase in the depth of the game.

It’s possible for games to go too far. I found GTA IV extremely frustrating because there was hour upon hour of tutorials for the many different mechanics that were added, which all needed their own tutorial, and which were not really skip-able.

It will be very interesting to see what the next two editions of these games are like. The third Assassin’s Creed game is likely to be set in the game’s near-future setting. I was thinking that I would like to see a 19th-Century setting, but I presume they won’t go for a third historical setting, though it is possible.

Overall, both sequels are excellent; I recommend them to anyone who might like them.