Back from the Dead: Despite exploding in the first episode, Kiba comes back to battle SKL again.
Berserk Button: Ryo really doesn't like the concept of fate. Galan telling him "Your fate is sealed" in Episode 2 enrages him so much that he insists upon fighting Galan despite earlier mocking Ken for indulging in a one-on-one swordfight.
BFS: SKL's Sword, Ganzantou, which is even bigger and more fearsome looking than Mazinkaiser's Kaiser Blade. Its hilt can also extend to become a massive polearm-like weapon).
Blade on a Stick: Ryo can combine the Breast Triggers into a long-handled poleaxe.
Blood Knight: Ken and Ryo both claim to be men who don't feel alive without battle, even stating that gods shall be cut and devils shot because they are in their way. This is a recurring theme in Mazinger-related boasts (Mazinger Z could make its user a god or a devil, Mazinkaiser could kill gods and devils).
The Cameo: Characters resembling Mazinger Z's mains appear in brief snippets in Episode 3: Kouji and Sayaka lookalikes are in a restaurant, Lori is the reporter, and the general who refuses to give Yuuki information on Iron Kaiser looks like an older Boss.
Caped Mecha: It doesn't seem to be part of its standard equipment, but on some scenes SKL appears wearing a ragged dust-cloak, in the style of Sandrock Kai or the Crossbone Gundams.
Cloning Blues: Strongly implied for Ryo, given what little we see of his past in this brief series. His Journey to the Center of the Mind , as well as a sequence in the opening, shows him surrounded by identical copies, and he says he fights to prove his own existence.
Cool Horse: In the ending of the final OVA, Mazinkaiser dual wieldsa spear and its signature BFSwhile riding on a mecha horse that transforms from a mecha motorcycle.
And the horse has skeletal bat wings to boot
Crystal Spires and Togas: The people from the Hachiryokaku faction seem to be modeled after this trope; including the pilots of the Psycho Gears, that fight while clad in togas and jewelry.
Disposable Pilot: Captain Scarlet pilots the SKL's supporting unit, Wingle, but also pilots the plane transporting her crew behind Gravity Wall. The plane crashes, she dies and her role as Wingle pilot is taken by Yuki Tsubasa.
The Engineer: Tsubasa Yuki, a female pilot working alongside the SKL duo.
Evil Knockoff: Although named otherwise, the Iron Kaiser is actually like this towards Grendizer! It even has its own version of the Double Harken!.
Eye Scream: Near the end of the Curb-Stomp Battle above, Mazinkaiser evades a spear meant for the cockpit, sending it into its right eye instead.
Freeze Frame Bonus: Wingle's computer screens display relevant text from Wikipedia when Yuuki goes looking for information (showing text from the "Robot" article when she tries to identify Iron Kaiser, and from "Gravity" when the Gravity Prison starts going haywire).
The Gunslinger: Ryo Magami. He seems to be a Type C according to the related tropes...
Dual Wielding (SKL's Breast Triggers are specifically designed to it)
Energy Weapon: Pulse Burst Mode, seen only in the last episode.
Gun Fu (With lots of acrobatics and close distance action)
Hatedumb / Ruined Forever: The announcement of this OVA has triggered a lot of flack from the fans of Shin Mazinger, who see it as an irrefutable proof that there won't be a sequel to it.
Of course, this may be completely undeserved hatred, given the rumours that SKL IS the sequel to Shin...
Two mass-produced mechas among the bad guy's army, GRK-7 and DBM-2, are based on Garada K7 and Doublas M2, the first Mechanical Beasts that Mazinger Z ever faced, and two recurring adversaries that have shown up in almost every adaptation of its mythos.
The Psycho Gear's pilots are named after Cutey Honey transformations.
The appearance of Tsubasa Yuki's mecha, Wingle, bears an uncanny resemblance to the eponymous character from Devilman Lady. It also the successor of the female-shaped robots from other Mazinger series, like Aphrodite A, Venus A and Minerva X.
The crest that becomes SKL's Breast Triggers is shaped like Devilman's head.
When Yuuki tries to identify the mystery mecha (Iron Kaiser) in the final episode, Wingle's computer compares its silhouette to the mecha from this show and several Ro Beasts from the original Mazinger Z.
Ken, after waking up Ryo from his unconsciousness says "If we died this easily, Great King Emna would be pissed!"
Red Oni, Blue Oni: Ken Kaido and Ryo Magami, the SKL pilots, are built around this dynamic. Even their signature fighting styles (meele and range, respectively) are diametrically opposite.
Redshirt Army: The Psycho Gears appear to fulfill this role.
She-Fu: You might not want to underestimate The Chick Tsubasa Yuki.
Nor the Octagon warriors! for once in Mazinger, Fem Bots are shown to be useful!
Ken and Ryo's codenames, Amon and Lucifer, are obviously shout-outs to the protagonist and antagonist, respectively, of Go nagai's other big work, ''Devilman.