idk if this has been mentioned before, but there's an infinite XP glitch in Mario's house involving the robot in the secret library room. If you enter the room and leave without selecting "Continue," you get the XP again upon re-enterin and you can keep doing this indefinitely. Please don't fix it.
And one more bug or not idk: the guide says you can meet Samantha and Ken at StarCon, but after waiting about 20 minutes (maybe 15) and clicking the chat window at the meet-and-greet, I didn't catch them. I know it all depends on luck, but...