I found all the star pieces, got all the recipes, and completed all the trouble requests. I was only missing a couple badges and didn't clear the Pit of 100 Trials (I made it to level 90).
Outside of Chapters 3 and 6, and the beginning of 7 where you have to chase General White around, I really enjoyed this. I found those 3 spots to be extremely tedious. While optional, I also found the Pit of 100 Trials to be very tedious, since, unless you luck into a bunch of the creature that you can pay to skip some levels, you have to spend a lot of time fighting battles that are a cakewalk to make it back to where you last left off if you decide to leave (it does get pretty tough in the second half), as the badge that lets you auto-win those battles doesn't work. You're going to need a few hours available if you do want to try to tackle the Pit. The Bowser segments initially had me chuckling, but they wore thin pretty quickly. The Princess Peach segments also had a short stay in the entertaining realm. Did they really think people would have fun having someone say "I love you" literally 100 times? I also shook my head when I decided to see what would happen if you choose the wrong option leading into the end battle and it actually gave me a Game Over, requiring me to sit through the ~5 minute lead-in that is unskippable.
Now that I know that you get absolutely nothing for finding all the star pieces and getting all the recipes, if I ever replay this, I won't try for all of them again.
