Adaptation Displacement: Few people know that Unleashed is actually a remake of Chakra-X's first fan film called The Power of Nazo.
Awesome Animation: The animation is one of the reasons this series is so popular. The character designs look like they could have been designed by the Sonic Team themselves, and the fight scenes are amazingly epic.
Awesome Music: Being a fan animation of a series famous for this, the series uses songs from various games in the series to its fullest potential to make the action much more awesome.
Complete Monster: Nazo was formed from the negative energy of the Chaos Emeralds, and desired to steal the Emeralds for himself for the purpose of gaining more power. After stealing a Chaos Emerald from a city, Nazo decided to destroy the city and kill all of its inhabitants for his own amusement. When he defeats Knuckles, Sonic, and Shadow, Nazo later brutally kills Tails for interrupting his attempt to kill Sonic. After he uses the Chaos Emeralds to transform into Perfect Nazo, he reveals that, because the Master Emerald will always have more power than him, he'll destroy the Earth and cause the Master Emerald's shattered pieces to spread throughout space, all out of envy. He also states that when he defeats the heroes, he'll go on to destroy the entire universe.
Evil Is Cool: A major amount of the appeal of the story is to see the titular Nazo kicking the asses of Sonic and Shadow nonchalantly.
Funny Moments: Shadow pulling out a gun and pointing it at Nazo's head. Made even funnier with Tails and Sonic's reactions; Tails is in awe and proclaims it as "cool" (even funnier because canonically Tails is 8 year old) and Sonic simply facepalms at Shadow's choice of weapon. And finally, when Nazo notices, he simply nonchalantly strikes Shadow with an elbow, launching him away.
Nazo originally being a silvery blue alternate take of Super Sonic planned for Sonic X is funny considering Dragon Ball Z: Resurrection 'F''s release, which introduced Super Modes for Goku and Vegeta that gave them a cyan blue hair as opposed to their classic yellow/gold Super Saiyan forms.
Sonic Forces would have its secondary antagonist, Infinite, introduce himself using the phrase "for the last moments of your life, you may call me Infinite." This is not too dissimilar to Nazo's own Badass Boast in the third part after he transforms into Perfect Nazo.
The animation's Dragon Ball Z-inspired fight scenes end up being oddly prophetic with the release of Sonic Frontiers, which would give Sonic and by extension, Super Sonic, a much more sophisticated, melee-oriented fighting style, complete with large-scale cinematic boss fights that wouldn't feel out of place from DBZ.
Images of Sonic and Shadow, Shadic's fusees, appear side-to-side with him as he obliterates Nazo after powering him down to his base form ends up becoming funnier as 14 years later, Super Saiyan 4 Gogeta was unveiled in Dragon Ball Fighter Z as the game's final DLC character and as he does the 100x Big Bang Kamehameha, images of Goku and Vegeta in their SSJ4 forms appear side-to-side to him.
What is supposed to be a sad moment in Tails' death ends up being hilarious when the reused "Sonic!" line for the moment is dramatically under-acted and whiny. This is probably the reason why it was changed to "Forgive me Sonic..." in the redux versions.
The sampled and recut voice acting from archived audio from the games can sound really awkward and forced at points throughout the original trilogy. This is one of the reasons why Chakra-X has stated he wants actual voice actors recording new, original dialogue for the sequel.
Perfect Nazo's voice can be this to some. While he was supposed to sound raspy and intimidating, the effect is mitigated slightly due to the fact that he speaks so low and softly that it can be rather hard to understand what he's actually saying at points, especially when the the music starts to kick in.
Nazo was already a somewhat popular fan character (due to his mysterious origin as a rejected Super Sonic design for Sonic X that wasn't revealed until much later), but his role as the main villain in this series has solidified him as one of the most recognizable fan characters within the Sonic fandom. He's since been frequently used in other fan works (notably The Return of Nazo, which gave him a cybernetic form that also gets used), put in the actual games via mods, and fans making sprite animations or fan games involving him.
Nazo's Master Breaker vs Shadic's Billion Ring Chaos Wind Beam-O-War sequence.
They Changed It, Now It Sucks!: Some had this reaction to Nazo Unleashed DX changing some of the music from the original, most notably using "Egg Nega Wisp Phase 2" in the 2014 edit in place of the "Gohan Powers Up" theme from the DBZ Bruce Faulconer score for Sonic and Shadow's Hyper Form Fusion Dance scene.
What Do You Mean, It's Not for Kids?: The original animation may star the family-friendly Sonic the Hedgehog characters, but it has some instances of swearing, bloody violence that is emulated from Dragon Ball Z, and a depiction of a semi-realistic firearm. Despite this, Nazo Unleashed DX was marked as "For Kids" by YouTube, which caused Chakra-X to re-upload the animation to the website while putting up a disclaimer within the first minute regarding this.
The opening already starts with a pretty great moment where Sonic questions how Knuckles lost the Master Emerald to Eggman again, with Tails unfazed by the whole debacle. Knuckles then explains that Eggman, disguised as a cleaner, wanted to polish it, to which Knuckles admits the gem was a huge "dust magnet".
Later, when Eggman reveals how the Master Emerald is attached to the Super Egg Carrier, Knuckles initially gets angry at its misuse, only to realize that the Emerald does actually look cleaner now.
Eggman's final words when he's about to be obliterated by Chaos Nazo? "Yosh."
Hilarious in Hindsight: Chakra-X posted the first animatic teaser trailer featuring Chaos Nazo's transformation on March 27, 2018. Dragon Ball Super: Broly would drop its first trailer, a few months later on July 19, 2018, which showed a very similar transformation sequence for Broly that matched the one used for Chaos Nazo in the animatic. The similarity and irony was not lost on him.
Among the many things people are pleased with in regards to the sequel is the change to actual voice actors instead of recutting dialogue from the games. People are especially impressed with Nathan Morrison's take on Sonic and Kyle Boyle's take on Eggman, both of whom manage to sound almost exactly like their contemporary voice actors in the mid-to-late-2010s and early-2020s (Roger Craig Smith and Mike Pollock respectfully) from the games.
Edwyn Tiong's performance as Nazo in this animation is not only a treat for the ears, but thanks to years of experience and acting in other projects, Tiong makes him sound incredibly smooth and threatening. His Vocal Evolution between Nazo Unleashed and Wrath of Nazo is quite noticeable.
Retroactive Recognition: Some might recognize that the voice of Shadow the Hedgehog is Connor "SenileSnake" McKinley, who first was casted and heard in teaser videos for Wrath of Nazo in 2015. This was before he later would appear in works associated with Team Four Star like Dragon Ball Z Abridged as Paragus in Broly Abridged, X in X Minutes, and HFIL as Cooler.
Chakra-X: "A little less DBZ inspired Nazo this time" my ass