I loved that Amiibo Trivia game. I will proudly say I managed to get all of them correct, although that last question stumped me and I had to think on it for awhile. Great inclusion!
As far as bad endings go, I really struggled with thinking of something. A lot of my favorite games, especially first party Nintendo games, have endings that are the least enjoyable part of the game (the third floor Boo hunt in Luigi's Mansion, Corona Mountain in Super Mario Sunshine, the backtracking of Chapter 7 in Paper Mario: The Thousand-Year Door, etc.) but none of them ruined the game for me. The Zelda series has several games where the last act of the game isn't as enjoyable for me (the Triforce hunt in The Wind Waker, the Ganon fight in Breath of the Wild, facing the Imprisoned and collecting Tadtones in Skyward Sword, etc.). If I had to pick one game with an ending I didn't really care for that kinda stepped a bit harder on my enjoyment of the whole package, I guess I'd go with Professor Layton and the Azran Legacy. I won't spoil anything, but I think the conclusion was not quite what my expectations were hoping for, and narratively, it spoils just a bit of the mystique of the prequel series' arc.