Noby Noby Boy is like Super Mario on an Acid trip.
My only real gripes with this game is that its camera controls are awkward for multiplayer, otherwise... its exactly what its advertised to be. The player floats around various environments eating things and stretching their Noby Noby Boy, while listening to relaxing music and watching people run in fear.
Singleplayer will not really entertain you for too long, the real joy of the game is local co-op! Teaming up with a friend to eat random objects and people on Mars is weirdly entertaining and engrossing. The game is completely non-threatening, making it excellent for children/stoners.
Overall Noby Noby Boy is a relaxing adventure, nothing more, nothing less.