Compared to the other 3D Mario platformers, It's not very complex or innovating. But the game does a great job at introducing new elements and ideas with every level, while never becoming overwhelming.
My main issue with some of the other 3D Mario's is that in their quest for unique and zany platforming they often create levels and worlds that end up more frustrating than fun. Mario 3D Land, in contrast, has quite safe level design. It never reaches the highs of 64 and Galaxy, but it never reaches their lows either. I don't think this is necessarily a bad thing.
Furthermore, while the lack of an interesting post-game is unfortunate, I still appreciate the main game very much for what it is: A relaxing, pleasant and charming Mario platformer.
My main issue with some of the other 3D Mario's is that in their quest for unique and zany platforming they often create levels and worlds that end up more frustrating than fun. Mario 3D Land, in contrast, has quite safe level design. It never reaches the highs of 64 and Galaxy, but it never reaches their lows either. I don't think this is necessarily a bad thing.
Furthermore, while the lack of an interesting post-game is unfortunate, I still appreciate the main game very much for what it is: A relaxing, pleasant and charming Mario platformer.