Is there a general pattern in how sequels turn out? Throw in your ridiculous theories about the life-cycle of games.
HALF-BAKED THEORY COMING THROUGH:
I'd say 1 is unpolished, experimental, sets up the idea of the series but still an immature, juvenile form, often prone to bugs and glitches.
2 is usually the best refined, most polished version of the series. (E.g. Borderlands 2, Mass Effect 2), but can also result in massive fan upset if the design change is rather radical or it's just a cash cow.
3 can be make or break, some can follow up on the success of their predecessor or become even better if there were underlying issues (Metal Gear Solid 4), others turn out to be highly controversial or mediocre (Fable III). Changing the formula or system at this point is often a no-no. Notable exception: Deus Ex HR > Deus Ex IW)
4, with a few exceptions, is where a series can have a great comeback after a mediocre third installment (Civ IV, Resident Evil 4), or an epic failure or just plain mediocrity after an attempt to reinvent itself. (Command and Conquer 4)
At 5, failure and mediocrity is much more likely than success no matter how good the series is.
There are genres excepted from all these general rules, such as JRPGs, which can keep going beyond even the tenth installment. Or sports games, which are often ten a penny, one every year.
HALF-BAKED THEORY COMING THROUGH:
I'd say 1 is unpolished, experimental, sets up the idea of the series but still an immature, juvenile form, often prone to bugs and glitches.
2 is usually the best refined, most polished version of the series. (E.g. Borderlands 2, Mass Effect 2), but can also result in massive fan upset if the design change is rather radical or it's just a cash cow.
3 can be make or break, some can follow up on the success of their predecessor or become even better if there were underlying issues (Metal Gear Solid 4), others turn out to be highly controversial or mediocre (Fable III). Changing the formula or system at this point is often a no-no. Notable exception: Deus Ex HR > Deus Ex IW)
4, with a few exceptions, is where a series can have a great comeback after a mediocre third installment (Civ IV, Resident Evil 4), or an epic failure or just plain mediocrity after an attempt to reinvent itself. (Command and Conquer 4)
At 5, failure and mediocrity is much more likely than success no matter how good the series is.
There are genres excepted from all these general rules, such as JRPGs, which can keep going beyond even the tenth installment. Or sports games, which are often ten a penny, one every year.