What's in a cliché? Games get a bad rap for leaning heavily on what we consider tropes like, for example, the exploding barrel. See a red barrel in a game and it's a safe bet you can shoot it to make it explode. Instinctively you know then that doing so when a bunch of enemies are nearby will blow them all up, and so you begin mentally preparing your strategy to take that into account. You duck and weave, shoot a few guys to get their attention and then lead them into position near the barrel ... and then you suddenly realize that what you once considered a cliché is actually an important aspect of level design - one of which you are more than happy to take advantage.
One man's cliché, therefore, is another man's core game mechanic. Or, looking at it another way, a cliché could just as easily be seen as part of an archetype. Games, after all, are as much a storytelling medium as they are interactive entertainment. If you feel like the whole "save the princess" thing has been done to death, you're not wrong. It has. But it's an important part of the recipe. One could just as easily say that using flour in muffins is clichéd.
Games provide you an excuse to perform otherwise meaningless tasks in a fun, engaging way. You need a reason to be mowing through enemies or jumping over obstacles. What's a better motivation than a damsel in distress? We're hardwired as a species to want to come to the aid of those in need, but would a dude stranded on the wrong side of town cut it? Fat chance. He can take a cab. But a kidnapped princess? The very idea represents not only opportunity but possible reward and subtextual romance. Rescue that princess and you're not just helping out a fellow human being, you're doing a favor for a wealthy and beautiful girl. Line up, boys!
The very fabric of games - all entertainment, really - is made up of such seeming clichés. Peer closely enough under the microscope, though, and you begin to see that these clichés are not mere embellishments, but part of the weave. The term "cliché" suggests a lack of originality, but adherence to an archetype like the kidnapped princess and implementation of accepted mechanisms like the exploding barrel are not so much creative laziness as they are entertainment shorthand. In other words, what's more important, originality in game mechanics and presentation or a creative, new way to blow up multiple dudes at once? If the barrel were instead a radioactive flower pot, and colored orange, would that really make for a better game?
One could just as easily say that guns are clichéd, and games would be more original if they had weapons made of fish. Or that instead of rescuing a princess, make it a poodle with a really waggily tail. Or, jettison the whole rescue thing altogether and make a game in which you fend off enemies and overcome obstacles ... just because? Or maybe you're the princess and the goal is to rescue yourself. These games exist, actually, but even they use exploding barrels. Because, hey, why reinvent the wheel?