What they did right: I know this comic isn't in the same universe with DC Super Friends, or Supergirl: Cosmic Adventures in the Eight Grade, but evil scientist Luthor is back, and hopefully evil CEO Luthor is going away. (At least something good is coming out of the Didio/Johns regression of the DCU.) Power Girl is given a secret identity, which I hadn't heard of before. (I checked the DC Wiki, and there she is. So it's not an original idea.) Batman is definately the TBATB Batman, but time will tell how many "Earth-1" elements will sneak their way in to be later contradicted by the cartoon, which DC has a sad history of in these "animated" books. All character elements work. Also, Luthor becoming evil has nothing to do with having his hair burned off. We learn that through the best thing they did, which is the Batman Secret Files on both him and Power Girl. It lets new readers learn who they are, and I hope they do this every issue. (With different characters. Duh.)
What they got wrong: No files on Aquaman and Carapax, the characters from the opening fight. Hopefully they'll be in the main story soon, so they can get their own file. However, the only real issue I have are the character models for Luthor and Power Girl. Power Girl looks like an old woman, and Luthor has big jowels, like he just merged his DNA with a bulldog.
Recommendation: I wasn't as excited reading this as I am most Marvel Adventures, but it's a fun story with better-motivated Luthor. Fix his and Power Girl's character models, and avoid being too tied to DCU Proper instead of the cartoon, and this shall be a good comic.