It's just a guess, but I am willing to bet the animated series based on the same name has generated a bit more buzz than its digital conterpart.
LEGO Knights Kingdom borrows from the classic tale of Good vs. Evil as you take control of several knights who set out on a quest to find a legendary weapon that will aid them in defeating the Dark Knight Vladek (mwahaha!)
The battles are extremely simple, which break down to nothing more than a hack-n-slash romp and the occassional use of magic spells to ward off attacks. Power-ups are peppered in ample quantities, however, I rarely saw the need for them since the enemy AI is set with the kid gloves on high.
Despite their size, detail and vibrance, the level design is extremely linear and lacks the desired freedom to explore. Further, I kind of wish that particular arc of the story progressed a bit faster as the first level (there are nine in total if you're keeping score) takes its sweet time picking up the pace. I am sure kids have a longer tolerance than me and can breeze through the game in under 10 hours or less.
Each area contains a relative degree of puzzles to decipher in order to advance, in addition to severall mini-quests that offer some added burst of entertainment. Ultimately, they're worth the effort if you want to expand your honor throughout the kingdom.
Players can also compete head-to-head (an option which sadly I couldn't take advantage of) in several events including Last Man Standing and Tournament Arena mode. By now, all the cool kids have gotten wiser and did away with their link cable and went wireless (get your folks to buy one for Christmas).
In all, the concept behind Knights Kingdom offers a decent level of gaming value (even if it's fairly on the redundant side) to hold the interest of younger players. And when that doesn't work, they can always run back to their building blocks and create their own fictional adventures.