I first switched on this game and was immediately reminded of my Mario 64 for obvious reasons. Most of the levels are based on the original but it does have some new mini-type worlds where you have to rescue the other characters etc.
These characters (Yoshi, Mario, Luigi, Wario) all have different abilities and you will only be able to complete certain levels whilst being a certain character.
I agree with "A gamer from Teesside's" that the levels are not wholly unique but I don't think this is detremental to the game (incidentally the 96 levels in Super Mario were not wholly unique either).
I agree also that using the thumbstrap is awkward, however do try using the stylus pen in "Dual Hand Mode". You have greater control and you can use it left or right handed.
The mini games are very good and the unlocking of these games will probably provide greater motivation to complete this game for gamers who have completed Mario 64.
Good game