In essence CNK is just a repeat of Crash Team Racing for the PS2 and ultimately looks boring and average in comparison.
CNK sticks to the previous Crash Racer like no game before it. With the exception of a few modified weapons, some new characters and a slightly shorter list of tracks, CNK really doesn't deviate a lot from CTR. This is not an entirely bad thing as CTR was an instant classic but CNK just looks boring and lazy in comparison. Even the story line is the same as an alien race is threatening to destroy earth unless Crash and his friends beat them in an intergalactic race. Its all been done before and is quite boring.
CNK is however a solid game in its own right. The game is slightly harder than CTR as the controls are less responsive and there is fewer opportunities to cheat and use powerups in order to beat an opponent. Most of the levels are fun but none are on the level of Oxide station, Cortex Castle or Polar Pass. Indeed many of the levels are incredibly similar to some of the levels in CTR, again reinforcing the lack of effort found in this game.
However CNK does have more accessible characters than its predecessor. CNK uses a sort of team powerup where players can race with one member of their team and work together by generating powerups and gang up to eliminate opponents. This at least adds something to a game which is overall just too similar to CTR to be considered a good game in its own right.
Overall CNK is a solid if unspectacular game which borrows heavily from its older brother. It is quite simple to get into and does have the level of difficulty needed to satisfy many gamers but it just doesn't deliver on the scale of CTR.