These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Joe And Mac
That One Boss: The dinosaur skeleton in level 10. The fight itself is fairly easy, but for the first half of the fight, instead of displaying a hurt animation, the skeleton just breaks apart and showers the screen in bones in an attack that's nigh-impossible to dodge, and can very easily just turn into the player and boss trading hits (and since the boss has more health than you, you'll die at least once.)