Awesome Music: Most, if not all, of the music tracks are remixed versions of the originals. Most, if not all, of the music is awesome. Mostly because they just took awesome music from other video games.
Complaining about People Not Liking the Show: Some of the developers of this game are known to get defensive and even retaliatory if anyone even mildly criticizes anything done in this game, whether it is level design or enemy placements. It's gotten better.
Demonic Spiders: The Flood corrupted Pansers are even more aggravating than their original counterparts due to how much faster and more aggressive they've become. They're dangerous even when alone.
Wart's Nightmare, the final level, and the monsters of Super Mario Bros. 2 become corrupted, decayed, and distorted by the parasitic Flood. Seeing what happened to the cute, cheery enemies is even more unsettling when they explode when defeated.