Video games are usually different. Designers often will listen to what made the original so great, what the players liked the best about it, what worked and didn't work and try to compile that into one giant improved sequel. Most of the time it works and in many cases video game sequels (at least in my experience) have been better playing and better looking games. Metal Gear Solid 2 played much better than Metal Gear 1 and Half Life 2 took the open world physics based one of the original and ran with it. No longer were confined to a single base but a huge alien infested world to explore.
Just like movies though, not all sequels get it right. Developers, like directors have a knack for "overcooking" the formula which makes their prequels great. "You liked fighting that enemy? Well how about you fight him three more times in this game."
Metal Gear Solid 2, while having a great game play suffered in the story department where a convulted, overly complicated story line made nearly everyone loose interest in the story and characters. The story in 1 was relatively simple with a few twists, but overall it had a clear villain, clear goal, and made you follow along as the characters worked towards their goal. 2 had none of this, instead opting for twists and philosophical banter from the characters instead. Good idea for a book or movie, but not for a video game (at least not in this context).
Finally you can get a sequel that really isn't all that different from it's predecessor. Bioshock 2 had a new playable character and story but it still felt very similar to the original, almost more of an expansion rather than a sequel. Despite the differences and tweaks the game still played largely the same and the same tactics and techniques could be used in the sequel. Even the story while different, was similar to the original and did not contain as many unique plot elements as the first. Developers usually stick to this similarity formula for two reasons: Their development cycle is shorter than other studios, which is why the Call of Duty series is so similar to each other with each of the development studios both Treyarch and Infinity Ward having little over a year to get their games up and running. The second is the fans. Fans like what the studios keep making, which is justified through the sales and hours of playtime online. Games which have a very large fanbase have to be careful not to alienate this audience. Radical changes to the game play or even story and characters can have the potential to turn of long time fans and potentially loose a large chunk of money.
I for the most part enjoy video game sequels, especially if I enjoyed the originals so much. I cant help but wonder though how easy it is for me to analyze and critique what developers did wrong and right in their sequels and a development team spends countless hours and sleepless nights to make sure their game ends up hitting that magic spot and pleasing everyone, when in most cases it won't.
Meh, I try not to think to much about that. Back to Moder Warfare 2 for me.