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.
Ass Pull: Andross (not to mention every sequence that involved an Arwing) was thrown in at the last second, even though an entire fight sequence between the Fox character and Scales had been programmed, complete with dialogue already recorded. This is why his addition feels so out of place and tacked on.
That One Level: Let's see, there's the Krazoa Test of Fear which will make even the most patient gamers toss their controllers in a fit of rage, then the Lightfoot Test of Strength which only the most button-mashing-happy will have some chance of beating it the first time off (which ironically the reward of beating this will give you access to aforementioned Krazoa test), or the egg thieves (until you learn that the easy way to beat it is to use your Groundquake, which miraculously doesn't crush the very eggs you're supposed to protect).
Viewer Gender Confusion: It's not uncommon to hear fans refer to the Shopkeeper as a "she". The character is actually male, but he has a voice that makes him sound like an old woman (which is actually provided by a man).