This is a spiritual sequel of Mario's Secret Weapon, this is also the sequel of Mario's New Secret Weapon.
Most of this was done by the time Part 1 came out; which I suggest you watch before watching this; Part 3 should be out quite soon, but considering Mario Kart Wii comes out today, maybe not...
I feel that this part is the weakest of the three parts; but that doesn't mean it's terrible.
Also, make sure your screens brightness is high enough; otherwise you may not see some things.
Full credits will be given in the conclusion.
NOTE: Part 3 is out now.