While puzzles can provide a dash of variety, developers must be careful not to make them too far removed from the rest of the game.
Used properly, puzzles can enrich a game immeasurably, and few gamers could honestly say that there isn't satisfaction to be had in conquering some fiendish obstacle with nothing but raw brainpower. Not all puzzles are created equal, however, and in Issue 284 of The Escapist, Katie Williams talks about how a puzzle that's too hard or obscure can suck all the immersion out of the room.
I've gone to hell and back (like, literally. It's full of lava and machinery down there). As Silent Hill: Homecoming's war-weathered Alex Shepherd, I have defeated all manner of enemies, from run-of-the-mill scythe-headed fleshbags to the monstrous, porcelain-doll reincarnation of a murdered child. I have survived everything this labyrinthine horror of a town has built around me - a crumbling hotel, stinking sewers, and a graveyard teeming with ravenous, skinless dogs. I have finally found my way back home, where I am to discover the gruesome secret my family has kept for generations - the reason for my younger brother's disappearance and the town's rapid decline into disrepair.
After all I have been through, however - after all the terrors I've endured and the monsters I've barely escaped - I am finally defeated by what lies behind the attic door. It is no monster. It is something much, much worse.
The key to the Shepherd family secret is a sliding puzzle.
After twenty minutes of this exercise in frustration, any semblance of immersion I may have felt has dissipated, fog turned to a cold, hard rain. I turn on the lights, scrambling for a walkthrough. Alex Shepherd and I are no longer a resilient team of grim and steely determination. He is merely my avatar, a somewhat grumpy mess of pixels - and I am the player, suddenly reminded of why I chose videogames over my plastic sliding puzzles as a child.
Williams argues that the best puzzles are the ones that are more integrated into a particular game's world, and not something shoehorned in to provide a "challenge." You can read about it in more detail in her article, "Puzzling Worlds."