Responding to Bob’s “games provide much more than a cognitive workout”…
Growing up in the 80s, video games were much less sophisticated and probably less effective as a matrix for training consumption. TV performed that role. I remember watching on Nickelodeon competitions between children in a toy store in which each contestant had 60, or 120 seconds to fill a shopping cart with as many toys as they possibly could. The winner — whoever had managed to grab the most — got to keep the contents of their cart. The physical challenge of the game was obvious. You could even argue that it presented a cognitive challenge insofar as you had to strategize the most effective pattern through the aisles, balancing the desirability of toys with their geometric propensity to fly off the shelves quickly. But did that excuse the game ethically?
I’ve played a bit of Katamari lately and have enjoyed it. It’s a world charged with static electricity, everything sticks. Each object has been lovingly rendered in its peculiarity and stubbornness. If your katamari picks up something long and narrow, say, a #2 pencil, and attaches to it in such a way that it sticks out far from the clump, it will impede your movement. Each time the pencil hits the ground, you have to kind of pole vault the entire ball. It’s not hard to see how the game trains visual puzzle-solving skills, sensitivity to shape, spatial relationships (at least virtual ones), etc.
That being said, I agree with Bob and Rylish that there is an internal economy at work here that teaches children to be consumers. A deep acquisition anxiety runs through the game, bringing to mind another Japanese pop phenom: Pokémon. Pokémon (called “Pocket Monsters” in Japan) always struck me as particularly insidious, far more predatory than anything I grew up with, because its whole narrative universe is based on consumption. “Collect ’em all” is not just the marketing slogan for spinoff products, but the very essence of the game itself. The advertising is totally integrated with the story. Here’s Wikipedia (not a bad source for things like this) on how it works:

“The Pokémon games are role-playing games with a strategy element which allow players to catch, collect, and train pets with various abilities, and battle them against each other to build their strength and evolve them into more powerful Pokémon. Pokémon battles are based on the non-lethal Eastern sport of fighting insects, but the Pokémon never bleed or die, only faint. The game’s catchphrase used to be “Gotta catch ’em all!”, although now it is no longer officially used.”

Similarly, the Katamari backstory involves the lord of the universe getting drunk one night and shattering the solar system. Each level of the game is the reassembly of a star or planet. If you succeed, a heavenly body is restored to the firmament.

After an hour playing Katamari, having traversed a number of wildly imaginative landscapes (and having absorbed a soundtrack that can only be described as Japanese chipmunks on nitrous) I re-enter the actual world in a mildly fevered state. The cardinal rule in the game is that to succeed I must devour as much as possible. No time is afforded to savor the strange, psychedelic topography, to examine the wonderful array of objects (everything from thumbtacks to blue whales) scattered about in my path. Each stage is a terrain that must be gobbled up, emptied. A throbbing orb of light in the upper left corner of the screen, set within concentric rings representing target diameters, measures my progress toward the goal: a katamari “n” meters in size. The clock in the upper right corner pressures me to keep rolling.
Video games today may not be as blatant as the consumerist spectacle of the Nickelodeon game, and they may provide richly textured worlds posing greater problem-solving challenges than any electronic media that has preceded them. But it seems to me that many of them do not differ ideologically from that shopping cart contest.