Playing Legend of Zelda: Twilight Princess last night on the Wii, I got to thinking about what makes it and other games like it so good, and I fell asleep last night thinking about variety in gameplay. By that, I mean being able to engage in a number of drastically different activities so as to avoid monotony.
Twilight Princess definately has this variety, as exhibited in the swordfighting, goat-herding, fishing, sumo wrestling and wolf-howling. All are drastically different types of gameplay, and serve to keep the game fresh as you play.
Perhaps the first example I remember encountering of this was the mock-swordfight you engage in as part of a theatre act early in Final Fantasy 9. At least, I think it was nine - I haven't played too many Final Fantasy games, and I can't remember the numbers well. That game had you press different buttons and measured your reaction time to determine success. I didn't see that particular mechanic until years later in games such as Indigo Prophecy and God of War, and both of those games improved on the concept. Minigames are in fact one of the primary ways developers go about introducing variety into games. I remember excellent minigames in such ancient titles as Legend of Blacksilver on the Commodore 64. But a line must be drawn: where minigames like the ones in Jade Empire serve to introduce variety (I love the RiverRaid-esque games), the so-called minigame added in Resident Evil 4 is nothing more than more shooting. Shooting targets and shooting insane villagers isn't that different. Far be in from me to disparage Resident Evil 4 on that basis - the game was excellent. And set pieces such as the spearfight versus the lake creature and the mine cart battle certainly introduce variety into that game, if not as much as exists in some others.
And there are certainly many games without a depth of variety that are still excellent games. Shadows of the Colossus comes to mind - battling colossi after colossi certainly isn't varied, although the colossi are as different from each other as colossi can be, but it's still an excellent game. Likewise with many shooters. Far Cry and Chronicles of Riddick didn't have a ton of variety, but were both incredible games.
This brings me to my grand finale. I think this notion of variety is one of the things that makes Beyond Good and Evil truly great. In that game, you've got fighting, vehicle driving, platforming, first-person shooting, puzzle solving, item collecting, and my favorite - stealth. Add to that a great storyline, and you've got a winning game. Oh - and it's got an air hockey minigame.