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.
Crowning Moment of Funny: Waluigi unsealing Psycho Iris and finding out that he was cursed into the form of an eggplant. His attempt to intimidate Waluigi doesn't really help his credibility, either.
Crowning Music of Awesome: The soundtrack is comprised of remixes of songs from bothWario series, themes associated with Waluigi and even other Nintendo games, along with new songs made specifically for the game. Almost entirely done in Mp3 format to boot!
The one song in the game that is rendered as a MIDI still manages to sound amazing. "The Final Conquest" the last stage, is a remix of a song from Mario Kart, redone to sound like a Banjo-Kazooie or Donkey Kong 64 type boss theme. Despite being a MIDI, it sounds amazingly authentic for what it's meant to invoke.
The boss music for that level is also pretty memorable, as it's a remix of "Destruction Dance" (Waluigi's boss theme) from Super Mario DDR.