Caution: Spoilers follow!
I know my limits so have declared 241/242 stars in Super Mario Galaxy 2 as being finished… The final level is only for obsessed people with too much time on their hands!
I am still not sure how this game was rated as highly as it was (although I do think it was a great game). It has a 97% average on Metacritic, making it amongst the highest rated games of all time. However, the only real addition to the gameplay from Super Mario Galaxy is “hide-and-seek”. I played that as a kid years ago so that is hardly novel… And it is not just one type of hide-and-seek; it is used multiple ways. First you have to find the Comet Coins to unlock a challenge on each world. Then once you have done all those levels (and beaten the final boss yet again – probably for the third time…), there becomes another 120 green stars that are hidden across the game. You think with all that practice the game designers would be good at hide-and-seek, but a fair portion of the things you have to find are clearly visible in the opening sequence for each world, which kind of ruins the whole point. In fact, I’m not sure there was a point at all other than to force you to constantly repeat the same levels.
But the game was saved by a review I watched beforehand, where we are told to think of “cake” as a Mushroom Kingdom codeword for “sex”. It made the Bowser’s final words rather amusing!