Awesome Music: The theme song is Cyborg 009, as covered by Jam Project.
Fanon: Due to the setting being fusion of both series, some have hopped this would actually result in a happier ending with Akira able to assist the cyborgs in the aforementioned God's War, and the cyborgs likewise being present to assist in Satan's inevitable uprising.
Fridge Horror: Due to the nature of the crossover, it's hard not to feel worried for the 00 Cyborgs, considering that they will have to experience Devilman's ending... Vice versa for Devilman if one were to take God's War into consideration. However, see Fanon.
The prologue, which showcases both the Cyborgs fight with the Mythos Cyborgs and Devilman's fight with Jinmen in perfect, one for one tone. Bonus points go for the latter, as other adaptations of the Jinmen fight omit Sachiko in favor of Akira's mother - despite occurring in an alternate continuity, this battle between Devilman and Jinmen is one of the most faithful adaptations out there, even more so than the more well-known version featured in the second film of the OVA Trilogy.
While everyone gets a moment to show off an impressive feat of combat, special mention goes to 009 for using his Accelerator to launch himself into orbit in order to come crashing back down directly on Atun's head, giving Akira the opening to use his fire beam.
Unintentional Uncanny Valley: Dr. Adams has a streamlined design that appears very much in line with modern manga and anime, which contrasts heavily with the retro 1960's design of the other Black Ghost scientists. As a result, seeing his more realistic face next to the cartoonishly exaggerated faces of the other scientists on Ryo's computer is just jarring.
The Un-Twist: To anyone who read the theatrical brochure, the reveal of Cyborg 0015 being Eva Maria Pallares shouldn't come as much of a surprise.
Demon General Zann is the head of the demon army and first of the two masterminds behind the events of the manga. Coming up with his master plan to bring victory to demonkind in their battle for Earth, with the assistance of his right-hand woman, Psycho Jenny, Zann brought the protagonists of the Cyborg 009 and Devilman universes into the devastated future version of Tokyo, as he then manipulates the Cyborg team and sends Psycho Jenny to pull the strings of Devilman army and Akira Fudo. As Zann took the form of Dr. Rainuma, he quickly gains trust of everyone around him, guiding the team into easily beating up Akira and later convinced Joe Shimamura to fight to the death with Akira by showing him a fake video of Akira murdering his Love Interest, Francoise Arnoul. As this resulted in two universes becoming one, Zann unleashes the demons upon humanity, after which he politely offers Lord Kokurei to join his ranks, having achieved everything he wanted.
Psycho Jenny is the second-in-command of the demon army and the second of two masterminds behind the plot. Assisting Zann in coming up with the scheme to guide demonkind in taking over Earth, Jenny helped Zann in teleporting the heroes of both universes to the destroyed future version of Tokyo, where she took the form of a little Devilman girl, called Mayumi, and manipulates Akira Fudo and the entire Devilmen army into attacking the humans, by playing the victim. Showing Akira the fake remains of Miki and blaming the Cyborg team for her death, Jenny tricks Akira into heading to fight Joe Shimamura and makes sure he won't hold back. Saddened by the fact that Ryo Asuka won't remember his true identity as Satan, Jenny then still got satisfaction in success of their plan.
