While the story was good, I can't get behind the aspect of J'onn being sent to conquer Earth. I knew it was probably coming. But this is the heart and soul of the Justice League we're talking about. This is just not kosher. Whether or not he decides to betray his Martian masters and defend the Earth doesn't matter. J'onn is not a spy. Someone really should start a lynch mob for the people at DC who decide to pull this crap!
Also, has it been confirmed that Mr. Biscuits is a Martian? With that drape covering his face, he could be pretty much anything. Also, I've never known Martians to snore from their armpits.