I've lost interest in any platform games since Donkey Kong 64, which I found so weak in gameplay. I always though Nintendo was number one in platform games, since now!
Ratchet and Clank: Up your Arsenal offer a new type of gameplay in the genre. Yeah, it's very much the same than it was in Going Commando, but we can't find better in any other platform games. You have more than 20 weapons, more than 10 gadgets to play with, all of this in a game running at 60 frames/second. Plus, there's a lot of replayability here, with a single player's mode of 15 hours+, a challenge mode and a brand new online mode with a possibility to compete against 7 people. A new addition to platform games.
And do not forget, there is a multiplayer game, great enough to play with your friends for hours and hours. This new episode is without a doubt the best platform game ever, with the first one in a 3d world, Mario 64 !!