This episode was great on a number of different fronts.
First we have a flashback to WWII which showcases not only an obscure WWII era superhero Spysmasher (I believe he was a Fawcett character, later acquired by DC), but the whole super-soldier thing looked to me like a sort of riff on Captain America, which may be some sort of subtle meta-text thing identifying DC's competitors with the Nazis, but anyway...
Eiling assuming the form of a gigantic, nigh indestructible engine of doom interestingly enough was actually from the comics, when his mind was implanted into a mindless artificial creature known as the Shaggyman (whose claim to fame, aside from looking like a buff Chewbaka, was that it was immensely strong and could adapt to anything thrown at it, basically it couldn't be beaten the same way twice). Eiling's look after injecting the super-soldier formula into himself is dead on for his appearance in the shaved Shaggyman body. The irony of having to become meta-human to defeat the meta-humans is rather obvious.
Finally, as an interesting bit for an old-school comic book fan such as myself, the composition of the group that took on Eiling, is in fact that of a WWII era superteam known variously as the Seven Soldiers of Victory, or Law's Legionaires. Star-spangled Kid (Stargirl), Stripesy (STRIPE), Crimson Avenger (who still hasn't had any lines), Shining Knight, Vigilante, Green Arrow and Speedy (who looks and sounds like his Teen Titans Go self, so this might be an indication of the two shows being in the same continuity).
The only thing that kept this ep from a perfect score in my mind was the rather pathetic way in which Eiling was stopped. Granted, I can see what they were aiming at, but I really wanted to see the non-metahuman superheroes manage to take him down.