I'd buy EA Games.
"But XoRn," you say, "EA games is worth 22.9 billion dollars?"
Well yes, and that's how I'll make my money.
If I can't cheat the system that way, then I'd buy Arc System Works. Using the remaining money I'd by the licenses for as many of my childhood tv characters I can and we would get a Street Sharks, Teenage Mutant Ninja Turtles, Swat Cats, Gargoyles, GI Joe, Freakazoid, The Tick, Power Puff Girls, Power Rangers/VR Troupers/Beetle Borgs, Rugrats, Angry Beavers anime fighting game. I imagine Stu from Rugrats would play exactly like Faust, just summoning exploding children or hurling them like bowling balls.